Hunted

>> I TAKE ALL MY CASES PRETTY PERSONALLY .>> Reporter: SHE WAS JUST STARTING HER SHIFT WHEN A CALL CAME IN .>> THE PATROL WAS BEING DISPATCHED TO A SEXUAL ASSAULT THAT HAD JUST OCCURRED .>> Reporter: GALBRAITH IMMEDIATELY HEADED TO THE SCENE ...>> RIGHT HERE IS THE BUILDING THAT THE GOLDEN VICTIM WAS LIVING IN AT THE TIME OF HER ATTACK .>> Reporter: ... AND SPOKE TO THE VICTIM, A 29- YEAR- OLD WOMAN WHO SAID SHE WAS IN BED WHEN SHE WAS ATTACKED .>> SHE REMEMBERED HEARING A NOISE, AND THEN A MASKED PERSON CAME INTO HER BEDROOM, STRADDLED HER, AND HE THREATENED TO SHOOT HER. HE HAD... HE HAD A GUN WITH HIM. HE SEXUALLY ASSAULTED HER, PHOTOGRAPHED HER AND HAD HER TAKE A SHOWER, AND THEN LEFT .>> Reporter: CRIME SCENE TECHNICIANS FOUND LITTLE EVIDENCE .>> HE TOOK EVERYTHING THAT WE COULD'VE COLLECTED D. N. A. FROM .>> Reporter: LIKE WHAT ?>> HE TOOK THE BED COVERS. HE INSTRUCTED HER, YOU KNOW, TO USE SOAP, TO USE TOOTHPASTE, TO BASICALLY WASH AWAY OR TAKE AWAY ANY OF THE EVIDENCE THAT WE NEEDED TO... TO SOLVE THE CASE .>> Reporter: BUT THE VICTIM DID REMEMBER THAT THE ATTACKER WAS WHITE AND BLONDE, BECAUSE SHE COULD SEE THE HAIR ON HIS ARMS .>> THIS VICTIM WAS VERY ARTICULATE. SHE WASN'T, YOU KNOW, VISIBLY SHAKEN. SHE WASN'T CRYING. SHE WASN'T EMOTIONAL .>> Reporter: SHE WAS ABLE TO SKETCH THIS IMAGE OF A MASKED MAN, AND THIS DISTINCTIVE EGG- SHAPED BIRTHMARK SHE SAW ON HIS CALF .>> SHE WAS ABLE TO GIVE ALL THESE VERY DETAILED BITS OF INFORMATION THAT AT SOME POINT IN THE INVESTIGATION, THESE ARE THINGS I'M GOING TO BE LOOKING FOR .>> Reporter: HER ATTACKER BROUGHT A PAIR OF PINK HIGH HEELS AND MADE HER WEAR THEM WHILE HE TOOK PHOTOS OF HER WITH A PINK SONY CYBERSHOT LIKE THIS ONE. OUTSIDE THE VICTIM'S APARTMENT, A SECURITY CAMERA RECORDED A SUSPICIOUS WHITE MAZDA TRUCK, BUT THE PLATES WEREN'T VISIBLE. AND IN THE SNOW, A SINGLE SHOEPRINT .>> AND IT CAME BACK AS AN ADIDAS. SO, WE KNEW IF WE COULD FIND THE RIGHT PERSON AND THEY WERE WEARING THAT SHOE OR HAD THAT SHOE, YOU KNOW, WE COULD BE A LITTLE BIT CLOSER .>> Reporter: BUT NONE OF WHAT THE VICTIM RECALLED WAS ENOUGH TO BREAK OPEN THIS CASE, AND DETECTIVE GALBRAITH-- NOW LEADING THE INVESTIGATION-- WAS DEEPLY FRUSTRATED. LATER THAT NIGHT, SHE DID WHAT MANY MARRIED PEOPLE DO AND VENTED TO HER SPOUSE, WHO JUST HAPPENED TO BE A POLICE OFFICER IN A NEIGHBORING TOWN .>> AND HE IMMEDIATELY JUST KIND OF LOOKED AT ME AND SAID, " YOU KNOW, I THINK WE'VE HAD THAT HERE IN... RECENTLY ." AND WHAT HE PICKED UP ON WAS THAT THEY WERE MADE TO SHOWER AND... FOR A CERTAIN TIME PERIOD AND BASICALLY WASH AWAY THE EVIDENCE .>> Reporter: FIRST THING THE NEXT MORNING, HER HUSBAND PUT HER IN TOUCH WITH THE LEAD INVESTIGATOR ON THAT CASE, 19 MILES AWAY IN WESTMINSTER,

DETECTIVE EDNA HENDERSHOT .>> IT SEEMED PRETTY OBVIOUS THAT THERE WAS SOME CONNECTION .>> Reporter: BOTH OF THEIR DEPARTMENTS ASSIGNED THE DETECTIVES TO WORK TOGETHER ON THE CASES. THE DESCRIPTION OF THE ATTACKER WAS ALMOST EXACTLY THE SAME .>> A WHITE MALE, ABOUT 6'2 ", 180 .>> HE HAD LIGHT COLORED HAIR .>> SHE ALSO DESCRIBED HIM AS A LITTLE BIT CHUBBY .>> I SAID, " MY VICTIM HAD A PINK SONY CYBERSHOT CAMERA THAT WAS STOLEN FROM HER ." AND STACY IMMEDIATELY KEYED ON THAT AND SAID, " MY VICTIM WAS PHOTOGRAPHED WITH A PINK SONY CYBERSHOT CAMERA ." >> Reporter: WHAT'S MORE, DETECTIVE HENDERSHOT WAS ABLE TO LINK THE RAPE OF 65- YEAR- OLD MARY IN AURORA TO THE SAME ATTACKER. THAT MADE FOR THREE ATTACKS IN TWO YEARS. AND, AT DETECTIVE HENDERSHOT'S CRIME SCENE IN WESTMINSTER, ANOTHER PIECE OF EVIDENCE .>> THERE TURNED OUT TO BE GLOVE IMPRESSIONS THAT WERE ALONGSIDE THE RAILING OUTSIDE OF THE APARTMENT WHERE THE WESTMINSTER VICTIM LIVED .>> Reporter: SO, NOT QUITE A FINGERPRINT .>> DEFINITELY NOT A FINGERPRINT .>> Reporter: BUT, BUT ...>> IMPRESSIONS FROM A GLOVE. AND WE DESCRIBED THEM AS A HONEYCOMB PATTERN .>> Reporter: WHAT'S THE PROFILE YOU HAVE ON THIS GUY? WHO DO YOU HAVE IN YOUR MIND? WHO IS THIS GUY ?>> WE'RE THINKING POTENTIALLY MILITARY. HE KNEW WHAT HE WAS DOING .>> I WAS KIND OF SCARED MAYBE HE COULD BE IN LAW ENFORCEMENT .>> I KIND OF FELT LIKE, LIKE, " DO ANY OF MY COPS HERE LOOK LIKE... LOOK LIKE THIS GUY? DOES ANYONE HAVE THIS MARK ON HIS LEG THAT OUR... MY VICTIM IS... IS DESCRIBING ?">> Reporter: IN ALL THE CASES, THE RAPIST TOLD HIS VICTIMS HE'D BEEN STALKING THEM FOR MONTHS, WATCHING THEIR EVERY MOVE AND BREAKING INTO THEIR HOMES DURING TEST RUNS. IF THEY COULDN'T STOP HIM SOON, THEY KNEW HE WOULD STRIKE AGAIN .>> HE'S HUNTING FOR HIS VICTIM, AND THEN THE NEXT VICTIM, AND THEN THE NEXT VICTIM .>> Reporter: DID YOU EVER CONSIDER THAT HE MAY BE A SERIAL KILLER AND NOT JUST A SERIAL RAPIST ?>> I THINK EVERYTHING WAS ON THE TABLE AT THAT POINT IN TIME .��>>\ MOST OF YOUR TIME IS SPENT \ FANTASIZING AND HUNTING .\ ONCE YOU KIND OF DECIDE, YOU \ KIND OF, YOU KNOW, ALMOST GO \ PAST THE POINT OF NO RETURN .;;;; COMMERCIAL ��>>\ AS YOU GET MORE PROFICIENT, \ YOU START MAKING LESS MISTAKES .��>> HE WAS EDUCATED ENOUGH TO KNOW WHAT WE WERE LOOKING FOR AND KNOW WHAT HE NEEDED TO TAKE TO THROW US OFF. HE WAS EXPERIENCED WITH WHAT HE WAS DOING. PROBABLY BE A LITTLE BIT DIFFICULT TO FIND .>> Reporter: COLORADO DETECTIVES STACY GALBRAITH AND EDNA HENDERSHOT WERE WORKING OVERTIME TO FIND THE PATTERN BEHIND THE ATTACKS .>> OUR VICTIMS SPANNED AGE RANGES. THE VICTIM IN AURORA WAS IN HER 60s. THE VICTIM IN GOLDEN WAS IN HER 20s. THE WESTMINSTER VICTIM WAS 59 YEARS OLD. TRYING TO FIGURE OUT WHAT IS IT THAT THEY HAVE IN COMMON THAT WOULD MAKE THEM TARGETS FOR THIS PARTICULAR INDIVIDUAL? THAT WAS VERY FRUSTRATING .>> Reporter: BECAUSE THERE WAS NO CONSISTENCY .>> THERE WAS NOT .>> Reporter: OTHER THAN THAT THEY WERE WOMEN. BUT THERE WERE PIECES OF A PUZZLE-- THAT GLOVEPRINT ON A RAILING IN WESTMINSTER, THE ADIDAS SHOEPRINT IN THE SNOW IN GOLDEN, AND A PINK CAMERA LIKE THIS ONE USED TO PHOTOGRAPH THE VICTIMS DURING THE ATTACKS-- BUT NOTHING TO PULL THE ENTIRE PICTURE TOGETHER .>> HE WAS COUNTING ON THE FACT THAT WE WOULDN'T TALK TO ONE ANOTHER, THAT WE WOULDN'T REACH OUT, THAT WE WOULDN'T COMMUNICATE. THAT'S WHAT HE WAS COUNTING ON .>> Reporter: BUT HE CERTAINLY WASN'T COUNTING ON THEM LOOKING FOR HELP, WHICH THEY DID WHEN THEY FORMED A TASK FORCE WITH LOCAL PROSECUTORS, THE COLORADO BUREAU OF INVESTIGATION AND THE F. B. I. ON THAT TASK FORCE WAS VETERAN F. B. I. SPECIAL AGENT JONNY GRUSING. DID YOU HAVE A SENSE THAT HE'S GOING TO STRIKE AGAIN ?>> ABSOLUTELY .>> Reporter: HE SCOURED AREA POLICE FILES FOR SIMILAR ATTACKS AND FOUND A REPORT IN NEARBY LAKEWOOD THAT WAS LABELED A HOME INVASION. BUT WHEN HE LOOKED CLOSER, HE SAW IT WAS A FAILED RAPE ATTEMPT, THE VICTIM DESCRIBING A MASKED MAN .>> AROUND 2: 33 IN THE MORNING, SHE HEARD A DRAGGING SOUND COMING DOWN THE HALL. THAT WOKE HER UP, AND SHE SAW A LARGE, MASKED MAN IN HER DOORWAY HOLDING A KNIFE. THEN, HE STRADDLED HER, MADE HER GO FACE DOWN. HOWEVER, SHE WAS ABLE TO ACTUALLY LIFT UP, TURN AROUND AND FACE THE MAN AND TELL HIM THAT HE... HE WAS NOT SUPPOSED TO BE THERE AND THIS WAS NOT GOING TO HAPPEN .>> Reporter: SHE'S WILLING IT NOT TO HAPPEN AT THIS POINT ?>> CORRECT. SHE WAS VERY BRAVE .>> Reporter: THE WOMAN STARTED SCREAMING A MAN'S NAME, YELLING FOR HELP. THE ATTACKER THOUGHT SOMEONE ELSE MIGHT BE IN THE LAKEWOOD HOUSE .>> AND HE MAKES THE DECISION HE'S GOING TO LET HER GO FOR A SECOND AND CHECK THE ROOM. BY THE TIME HE JUMPS OFF OF HER AND CHECKS THE ROOM, SHE GETS ON HER BED AND DIVES OUT A WINDOW THAT IS ABOUT ONE FOOT HIGH BY FOUR FEET WIDE, ONTO THE CONCRETE OUTSIDE. SHE SHATTERED HER VERTEBRA, THAT TWO RIBS WERE BROKEN, AND HER LUNG WAS PUNCTURED FROM THAT FALL. BUT SHE STILL GOT UP, RAN TO HER NEIGHBOR'S HOUSE AND CALLED THE POLICE .>> Reporter: HER POLICE FILE HAD BEEN SITTING DORMANT FOR HALF A YEAR WHEN THE DENVER AREA TASK FORCE FINALLY CAME ACROSS IT. THAT ONE CASE TURNED OUT TO BE A TREASURE TROVE FULL OF EVIDENCE AND INFORMATION THAT DEFINITIVELY LINKED ALL THE ATTACKS TOGETHER .>> THE EVIDENCE IN THE LAKEWOOD CASE WAS ABSOLUTELY KEY IN LINKING THIS TO ONE ATTACKER. SPECIFICALLY, EACH PIECE OF EVIDENCE FROM ONE OF THE OTHER ASSAULTS HAD A CONNECTION TO THE LAKEWOOD CASE. FOR EXAMPLE, THE GLOVE, LIKE THIS. THIS GLOVE PATTERN WAS FOUND IN THE LAKEWOOD CASE, AND THIS PATTERN WAS ALSO FOUND IN THE WESTMINSTER CASE .>> Reporter: AND REMEMBER THAT ADIDAS SHOEPRINT IN THE SNOW IN GOLDEN? THERE WAS A PERFECT MATCH IN LAKEWOOD. THEN, AT THE END OF A LONG TASK FORCE MEETING, A MENTION OF A SUSPICIOUS WHITE VEHICLE SEEN AT THE LAKEWOOD ATTACK .>> SO, THIS IS THE BULLETIN THAT THE CRIME ANALYST IN LAKEWOOD HELD UP AT THE CONCLUSION OF OUR MEETING .>> Reporter: IT DESCRIBED A WHITE MAZDA PICKUP TRUCK .>> THAT WAS WHEN I AM LIKE, " OKAY, WE HAD A WHITE TRUCK AND IT'S JUST LIKE THAT ." I JUST KNEW IN MY HEART THAT THAT WAS... THAT WAS IT. FOR THAT TRUCK TO BE IN THAT NEIGHBORHOOD IN LAKEWOOD AND ALSO BE IN MINE? THAT HAD TO BE SIGNIFICANT .>> Reporter: NOW, THE TASK FORCE HAD A PLATE NUMBER. AND WHEN THEY DUG THROUGH THEIR DATABASE, THEY CAME ACROSS THIS PICTURE OF THE TRUCK WITH A WHITE MAN STANDING NEXT TO IT, ABOUT SIX FEET TALL .>> WHEN I SAW THIS TRUCK AND THE MAN STANDING NEXT TO THE TRUCK, I THOUGHT THAT THAT LOOKED LIKE WHAT ALL THE VICTIMS WHO HAD BEEN ATTACKED DESCRIBED. THAT WAS THAT " AH- HA" MOMENT .>> WE HAVE A TRUCK THAT'S IN THE SAME TWO AREAS, AND NOW WE'VE GOT TO SEE WHO IT BELONGS TO AND WHO IS THIS GUY .>> Reporter: AND WHO WAS THAT GUY ?>> MARC O'LEARY .>> Reporter: HAD YOU EVER HEARD THAT NAME BEFORE ?>> NO .>> Reporter: WAS HE ON ANYBODY'S RADAR ?>> NO .>> Reporter: MARC PATRICK O'LEARY, A MAN FITTING THE VERY PROFILE DESCRIBED BY SEVERAL OF THE VICTIMS. HE HAD A MILITARY CAREER THAT TOOK HIM ALL OVER THE WORLD, FROM WASHINGTON STATE TO KOREA. THE 32- YEAR- OLD O'LEARY WAS SEPARATED FROM HIS WIFE AND STUDYING AT A LOCAL COMMUNITY COLLEGE. DID HE HAVE ANY PRIOR CRIMINAL HISTORY WHATSOEVER ?>> INSIGNIFICANT .>> Reporter: BUT NO ASSAULTS ?>> NO .>> Reporter: NO VIOLENT CRIME .>> NO .>> Reporter: NOTHING TO INDICATE THAT THIS GUY WAS CAPABLE OF WHAT HE WAS BEING ACCUSED OF .>> NOTHING LIKE THAT .>> Reporter: I MEAN, YOU GOT THE TRUCK, YOU GOT THE GUY, YOU GOT AN ADDRESS. HE'S RIGHT THERE. LIKE, DID YOU WANT TO JUST GET IN YOUR CAR, GO OVER, BANG ON THE DOOR AND TAKE HIM RIGHT THEN ?>> NO, WE COULDN'T DO THAT YET .>> Reporter: I KNOW YOU COULDN'T, BUT DID YOU WANT TO ?>> WELL, WE NEEDED TO MAKE SURE .>> AND SO, IT BECAME IMPORTANT AT THAT POINT IN TIME TO START CONDUCTING SURVEILLANCE ON HIM, ATTEMPT TO GET THE D. N. A. FROM THIS INDIVIDUAL .>> Reporter: MARC O'LEARY, SUSPECTED OF STALKING AND ATTACKING SO MANY WOMEN, WAS ABOUT TO BECOME HUNTED HIMSELF .>>\ TONIGHT'S " 48 HOURS" WILL \ CONTINUE .>> WE'RE IN LAKEWOOD, COLORADO, AND THIS IS THE NEIGHBORHOOD WHERE WE SET UP ON MARC O'LEARY'S RESIDENCE. WE WAITED AND WATCHED .>> Reporter: THE TASK FORCE FINALLY HAD A VIABLE SUSPECT IN MARC O'LEARY, AND AGENT GRUSING'S TEAM DIDN'T HAVE TO WAIT LONG FOR THINGS TO PICK UP, FAST .>> AND THEY SEE THE TRUCK LEAVE, AND IT LOOKS LIKE THE REGISTERED OWNER GETS IN IT WITH A FEMALE .>> Reporter: AS PART OF THE TEAM FOLLOWED THE COUPLE TO LUNCH AT THIS RESTAURANT, GRUSING STAYED BEHIND, HOPING TO INSTALL A SURVEILLANCE CAMERA ON THE HOUSE. BUT FIRST, HE NEEDED TO MAKE SURE NO ONE ELSE WAS HOME .>> I WALKED UP THROUGH THIS DRIVEWAY. WE KNOCKED ON THAT WHITE DOOR WHERE THE LIGHT IS, AND MARC O'LEARY APPEARED IN THE DOORWAY .>> Reporter: WHICH YOU WERE NOT EXPECTING ?>> I WAS NOT EXPECTING IT .>> Reporter: HE REALLY WASN'T. HE THOUGHT HE HAD JUST SEEN O'LEARY DRIVE OFF IN THE TRUCK. AND WHAT WAS HIS DEMEANOR WHEN HE CAME TO THE DOOR ?>> HE LOOKED A LITTLE SURPRISED. HE WAS CURIOUS, I WOULD SAY, MORE THAN ANYTHING TO SEE WHY WOULD WE EVEN BE KNOCKING ON HIS DOOR .>> Reporter: SO, YOU HAD TO DO A LITTLE TAP DANCE. WHAT HAPPENED ?>> I PULLED OUT THE FLYER THAT I HAD READY, AND IT WAS OF A PERSON WE WERE LOOKING FOR IN ANOTHER INVESTIGATION. HE LOOKED AT THE SKETCH, SAID IT DID NOT LOOK FAMILIAR. HE SAID THAT HIS BROTHER LIVED THERE WITH HIM. WE DIDN'T EVEN KNOW HE HAD A BROTHER UNTIL THAT MOMENT .>> Reporter: IT TURNED OUT GRUSING'S TEAM WAS TAILING MICHAEL O'LEARY, MARC'S YOUNGER BROTHER, WHO LOOKS AN AWFUL LOT LIKE HIM. THEY COLLECTED THE CUP THAT MICHAEL DRANK OUT OF AT LUNCH, HOPING THAT STRAIN OF D. N. A. MIGHT MATCH THE D. N. A. ON THAT TEDDY BEAR AND OTHER SAMPLES THEY OBTAINED. AND WHAT DID IT REVEAL ?>> IT REVEALED THAT STRAIN OF MALE D. N. A. FROM THE O'LEARY FAMILY WAS ON ALL OF OUR VICTIMS' POSSESSIONS .>> Reporter: BUT THEY HAD NO IDEA WHICH O'LEARY BROTHER WAS RESPONSIBLE, SO THEY WENT TO FIND OUT. WHAT ARE YOU FEELING? YOU'RE THIS CLOSE TO THIS GUY .>> I'M READY, AND I'M PRAYING AND HOPING THAT WE DON'T LOSE HIM SOMEHOW AND SOMEONE ELSE GETS HURT .>> Reporter: AT 6: 00 THAT SUNDAY MORNING, THE TEAM KNOCKED ON THE O'LEARYS' DOOR, GUNS DRAWN. STACY FOUND HERSELF FACE TO FACE WITH MARC O'LEARY .>> HE JUST WENT PALE. JUST, LIKE, YOU COULD JUST KIND OF SEE THE LIFE GO OUT OF HIM FOR A SECOND. HE HAD REAL BAGGY PANTS ON, SO I LIFTED EACH PANT LEG UP, AND I SAW THE EGG- SHAPED BIRTHMARK ON HIS CALF .>> Reporter: IT WAS IDENTICAL TO THAT UNUSUAL BIRTHMARK THAT GALBRAITH'S VICTIM HAD DESCRIBED ON HER ATTACKER'S LEG .>> I SAID, " TURN AROUND, PUT YOUR HANDS BEHIND YOUR BACK, YOU'RE UNDER ARREST ." >> Reporter: THEY KNEW THEY FINALLY HAD THE RIGHT O'LEARY IN CUSTODY .>> IT'S GRATIFYING TO FINALLY PUT SOMEONE LIKE THAT IN HANDCUFFS .>>\ LEAVE THESE OFFICERS HERE \ WITH YOU FOR JUST A MOMENT, \ OKAY ?��>> Reporter: MARC O'LEARY SEEMED STRANGELY AMUSED BY THE CIRCUMSTANCES ...>>\ GUARD DUTY, HUH ?(\ LAUGHS \) >> Reporter: ... AND HE WOULD NOT COOPERATE .��>>\ I JUST NEED TO TALK TO AN \ ATTORNEY .��>> AT THAT POINT, WE WERE WANTING TO SEE WHAT WAS IN THE HOUSE. >> Reporter: A SEARCH WARRANT OF HIS HOME YIELDED A GOLDMINE .>> HE HAD ALL OF THESE THINGS THAT HE USED TO FACILITATE THESE ASSAULTS, JUST IN PLACES ABOUT THE HOUSE .>> " HIDDEN IN PLAIN SIGHT" IS HOW I WOULD DESCRIBE IT .>> Reporter: HIDDEN IN PLAIN SIGHT .>> SO, IN HIS CLOSET, WE CAME UP WITH... WE CAME UP WITH THIS, HIS SHOES .>> Reporter: WHAT DID YOU THINK ?>> I KNEW THOSE WERE THEM .>> THAT'S IT .>> Reporter: THEY WERE A PERFECT MATCH TO THOSE SHOEPRINTS FOUND NEAR TWO OF THE CRIME SCENES. JUST INSIDE O'LEARY'S FRONT DOOR, A PAIR OF GLOVES WITH THAT DISTINCT HONEYCOMB PATTERN. AND THAT WASN'T ALL .>> THIS IS A PINK SONY CYBERSHOT CAMERA THAT WAS COLLECTED FROM THE OFFICE OF O'LEARY'S RESIDENCE. HE HAD, KIND OF, SOME BOOKSHELVES, AND HE HAD IT JUST KIND OF PROPPED UP ON A SHELF .>> Reporter: IT WAS THE EXACT CAMERA THAT WAS STOLEN FROM THE WESTMINSTER VICTIM AND USED TO PHOTOGRAPH THE GOLDEN VICTIM. AND THEN, PERHAPS MOST DISTURBINGLY, THEY CAME UPON THIS BACKPACK FULL OF ITEMS O'LEARY HAD BROUGHT WITH HIM TO PERPETRATE THE RAPES. SO, THESE ARE THE HIGH HEEL SHOES? WHICH VICTIM ?>> GOLDEN .>> Reporter: SO, THIS IS YOUR VICTIM ?>> YEAH .>> Reporter: YOU GET QUIET WHEN YOU SEE THEM ?>> YEAH. I... I ACTUALLY HAVEN'T SEEN THESE THINGS, BEYOND PICTURES .>> Reporter: WHY DO YOU GET QUIET ?>> IT'S JUST SAD .>> Reporter: YEAH .>> YOU KNOW, IT'S JUST A THING UNTIL YOU KNOW THE DETAILS OF WHAT THE THING WAS USED FOR .>> RIGHT. YOU DON'T USUALLY FIND THIS, IN MY OPINION, THIS MUCH CORROBORATION. THIS ...>> THAT'S ABSOLUTELY FAIR .>> ... CORROBORATED EVERY, I MEAN, JUST... TCH, TCH, TCH, TCH .>> Reporter: HE DIDN'T SEEM TO BE REALLY WORKING HARD TO HIDE EVERYTHING .>> HE WASN'T EXPECTING US .>> Reporter: BUT IN ALL THAT EVIDENCE, THERE WAS NOTHING TO LINK MARC O'LEARY'S BROTHER, MICHAEL, TO ANY OF THE ATTACKS. AT THIS POINT IN TIME, YOU DO NOT BELIEVE HE WAS INVOLVED WITH IT IN ANY WAY ?>> NO, NO .>> Reporter: IT WAS IN MARC'S ROOM, IN MARC'S POSSESSIONS, THAT THE

HARD DRIVES CONTAINING HUNDREDS OF PICTURES, AND NOT JUST OF THE FOUR VICTIMS THEY KNEW OF. DEPUTY JEFFERSON COUNTY DISTRICT ATTORNEY BOB

>> THERE WERE PHOTOGRAPHS THAT DEPICTED OTHER WOMEN IN WHAT I THINK CAN ONLY BE CHARACTERIZED AS A RAPE SCENARIO .>> I WONDERED IF THEY WERE VICTIMS OF SEXUAL ASSAULT, IF THEY WERE EVEN ALIVE ANYMORE .>> Reporter: THE INVESTIGATORS HAD TO FIND THEM. IN O'LEARY'S PHONE, THEY FOUND HE HAD CALLED THIS WOMAN NUMEROUS TIMES. HER NAME IS AMY. WE'RE ON OUR WAY TO MEET HER. AMY WASN'T A VICTIM; SHE WAS ACTUALLY O'LEARY'S GIRLFRIEND. NOW, CAN YOU IMAGINE, YOU FIND OUT THE GUY YOU HAD DATED WAS ACTUALLY A SERIAL RAPIST AT THE TIME THE TWO OF YOU WERE TOGETHER? I MEAN, WHAT WOULD YOU SAY? HOW WOULD YOU REACT? WE'RE ABOUT TO FIND OUT. HI, AMY. MAUREEN MAHER WITH " 48 HOURS ." NICE TO MEET YOU. HAVE A SEAT. THANK YOU SO MUCH .>>\ TONIGHT'S " 48 HOURS" WILL \ CONTINUE .>> SO, I WAS AT WORK, AND A MESSAGE WAS ON MY PHONE FROM SPECIAL AGENT JOHN GRUSING FROM THE F. B. I. REGARDING MARC O'LEARY .>> Reporter: IN EARLY 2011, THEN A 35- YEAR- OLD BARTENDER, AMY WAS UNSURE WHY THE F. B. I. WOULD BE CALLING HER ABOUT HER EX- BOYFRIEND .>> HE SAID, " WELL, I'M SURE YOU KNOW WHAT IS GOING ON WITH MARC O'LEARY. AND I SAID, " NO, ACTUALLY, I DON'T ." AND HE SAID, " WELL, IT'S BEEN ALL OVER THE NEWS. HE'S COMMITTED A SERIES OF RAPES .">> Reporter: IT WAS HARD FOR AMY TO BELIEVE. SHE'D MET MARC O'LEARY ON THE ONLINE DATING SITE OKCUPID IN 2009, AND THE MAN SHE THOUGHT SHE KNEW PRESENTED HIMSELF VERY DIFFERENTLY .>> HE WAS PRETTY CHIVALROUS AND PROTECTIVE AND ...>> Reporter: WAS HE CHARMING ?>> HE WAS VERY CHARMING. LIKE, HE WAS REALLY FUN TO TALK TO. WE TALKED FOR HOURS AT A TIME QUITE FREQUENTLY. THERE WAS A LIGHTNESS TO HIM, EVEN THOUGH HE HAD A DARK SENSE OF HUMOR .>> Reporter: BUT IT DIDN'T LAST LONG FOR THE COUPLE .>> WE ATTEMPTED A SEXUAL RELATIONSHIP, BUT THINGS DID NOT GO VERY WELL IN TERMS OF CHEMISTRY. MARK NEEDED THE OTHER PERSON TO BE SCARED .>> Reporter: THE FEAR ?>> YES .>> Reporter: AND THE DOMINANCE ?>> YES .>> Reporter: AND DID YOU EVER SEE THAT VIOLENT SIDE OF HIM ?>> NO. I DIDN'T SEE ANY VIOLENCE. LIKE, I KNEW WHAT HE LIKED AND WHAT TURNED HIM ON, BUT I DIDN'T SHOW HIM FEAR IN ANY REAL WAY, AND HE KNEW I WASN'T SCARED. IT WAS TOFU TO SOMEBODY WHO WANTED STEAK .>> Reporter: AMY HAD NO IDEA THAT WHEN SHE WASN'T WITH MARC, MARC WAS OUT PREYING ON WOMEN .>> I TALKED TO SPECIAL AGENT GRUSING FOR A LONG TIME. AND THEN, AFTER I GOT OFF THE PHONE, I WENT AND THREW UP. IT WAS PRETTY UPSETTING TO ME .>> Reporter: AS AMY STRUGGLED WITH MARK O'LEARY'S ARREST, A FEW MILES AWAY, A DETECTIVE BROKE THE NEWS TO MARY .>> FIRST, I DIDN'T BELIEVE HIM. I SAID, " YOU'RE SURE ?" AND HE SAYS, " YEAH, WE GOT HIM ." THAT'S WHAT HE SAID, " WE GOT HIM ." >> Reporter: DID YOU FEEL A SENSE OF RELIEF ?>> OH, MY, YES. YES. THERE WERE SO MANY VICTIMS, AND HE WAS SO SICK .>> Reporter: MARC PATRICK O'LEARY WAS CHARGED WITH MORE THAN 30 COUNTS OF SEXUAL ASSAULT, KIDNAPPING AND BURGLARY. PROSECUTOR BOB WEINER :>> TO HAVE ACTUAL PHOTOGRAPHS, AS DISGUSTING AS THEY WERE, OF THE ACTUAL RAPES ENDED ANY SPECULATION AS TO WHETHER WE HAD THE RIGHT GUY .>> Reporter: FACED WITH OVERWHELMING EVIDENCE, O'LEARY AGREED TO PLEAD GUILTY TO THE SEXUAL ASSAULT CHARGES ...>> HE WAS METICULOUS IN THE WAY HE STALKED THESE VICTIMS .>> Reporter: ... BUT IT WAS AT HIS SENTENCING HEARING THAT FIREWORKS REALLY BEGAN .>> I AM A SEXUALLY VIOLENT PREDATOR .>> SURPRISINGLY, HE HAD THE CHANCE TO ADDRESS THE COURT, AS WELL. HE TOOK ADVANTAGE OF IT .>> AND I'M OUT OF CONTROL. I'VE BEEN OUT OF CONTROL FOR A LONG TIME. WORDS ARE JUST INADEQUATE TO DESCRIBE HOW, JUST, HORRIBLE I, YOU KNOW, I ACTED. AND I CAN ONLY HOPE THAT, YOU KNOW, THAT MY SENTENCE TODAY WILL SATISFY THEM .>> Reporter: HIS SENTENCE WOULD MORE THAN SATISFY-- OVER 300 YEARS IN PRISON, A STAGGERING NUMBER .>> IN SOME CRAZY WAY, I FELT SORRY FOR HIM. HE SAID HE WAS JUST GOING FROM ONE PRISON TO ANOTHER. SO, HE WAS IN HIS OWN PRISON .>> Reporter: AND SOMETHING ELSE HE SAID AT THE SENTENCING CAUGHT THE DETECTIVES' ATTENTION .>> HE SAID THAT HE WOULD BE WILLING TO ANSWER QUESTIONS. AND IN LAW ENFORCEMENT, IT'S... THAT'S THE, YOU KNOW, THAT'S THE GREEN LIGHT .>> Reporter: THEY WERE ABOUT TO GET A RARE LOOK INTO THE MIND OF A SERIAL RAPIST .��>>\ ARE YOU OKAY ?>>\ YEAH, I'M ALL RIGHT .��>> Reporter: JONNY GRUSING TOOK THE LEAD, PLAYING TO O'LEARY'S EGO .>> I TOLD HIM THAT OUR PROFILERS WERE VERY INTERESTED IN HIM BECAUSE OF HOW INTELLIGENT HE WAS, AND HE SEEMED TO LIKE THAT .��>>\ YOU KNOW, YOU'LL HEAR \ PSYCHOLOGISTS AND SHRINKS WILL \ SAY, YOU KNOW, THAT RAPE IS A \ CRIME ABOUT POWER AND CONTROL .\ AND THAT'S NOT ACCURATE .\ POWER AND CONTROL ARE A MEANS \ TO AN END .\ BUT WHAT TURNED ME ON WAS FEAR .>> HE TALKED ABOUT HOW HIS PENDULUM WOULD SWING, AND HE COULD NOT CONTROL IT. HE WOULD HAVE TO FILL THAT NEED, AND THAT'S THE MONSTER TALKING TO HIM .>>\ AFTER A WHILE, THE... THE ( BLEEP )\ MONSTER KICKS IN .>> HE NEVER WON ANY OF THESE BATTLES WITH THE MONSTER .>> Reporter: AND GRUSING SAW THAT MONSTER UP CLOSE. O'LEARY DESCRIBED HIS FEELINGS AFTER ONE OF THE RAPES .>> I STILL REMEMBER THIS MOMENT. THAT'S WHEN HE LEANED BACK AND SMILED .>>\ I GOT SOME SATISFACTION .\ IT WAS LIKE I'D JUST EATEN \ THANKSGIVING DINNER .>> Reporter: O'LEARY SAYS EVEN AS A CHILD HE HAD RAPE FANTASIES BUT DIDN'T ACT ON THEM UNTIL HE WAS IN THE MILITARY, ON A TOUR OF DUTY IN KOREA, WHERE HE TRIED BUT FAILED TO RAPE TWO WOMEN. BACK IN THE STATES, HE WAS DETERMINED NOT TO FAIL AGAIN .>>\ SO, I'VE GOT TO DO IT FOR \ REAL AND JUST BE DONE WITH IT .>> AND THEN, HE DECIDED THAT HE WAS GOING TO USE HIS MILITARY TRAINING TO FIGURE OUT A WAY TO STALK HIS VICTIMS, TO NOT BE CAUGHT, AND TO SATISFY THIS URGE THAT WOULD COME .>> Reporter: O'LEARY BROUGHT UP ONE WOMAN HE'D BEEN PLANNING TO ATTACK .>>\ PECH, I THINK IT WAS .\ P- E- C- H .>> Reporter: JULIE PECH. REMEMBER HER? THE SINGLE MOTHER WHO HAD NO IDEA O'LEARY WAS STALKING HER .>>\ CHECKED OUT HER HOUSE A \ COUPLE OF TIMES .\ I KNEW SHE HAD AN ALARM SYSTEM, \ BUT SHE NEVER USED IT .>> HE WAS LINING HER UP FOR AN ASSAULT .>>\ AND SO, I WAS WALKING AROUND \ THE BACK OF HER HOUSE ONE \ NIGHT .\ JUST AS I WAS WALKING BY HER \ BACK BALCONY, SHE OPENED THE \ DOOR .>> I SAW HIM OUT THERE, AND I SAID, " WHAT THE (\ BLEEP \) ARE YOU DOING HERE? GET OUT OF HERE. I'M GOING TO CALL THE POLICE ." AND I JUST WATCHED HIM. HE JUST TURNED AROUND, WENT DOWN THE STAIRS, WENT OUT TO THE BACK, CLIMBED OVER THE FENCE AND LEFT .>> Reporter: JULIE, UNNERVED, ALWAYS SET HER HOME ALARM AFTER THAT BUT NEVER THOUGHT ABOUT IT AGAIN UNTIL THE F. B. I. CALLED HER .>> IT WAS VERY HARD FOR ME TO PROCESS IT .>> Reporter: BUT THE F. B. I. DIDN'T TELL HER EVERYTHING. DID YOU KNOW THAT AT ONE POINT HE WAS IN THE HOUSE AND YOU WERE ASLEEP ?>> I DID NOT KNOW THAT .>> Reporter: WALKING IN AND OUT OF YOUR HOUSE ?>> NO .>> Reporter: TAKING THINGS FROM YOUR PLACE ?>> NO IDEA WHATSOEVER .>> Reporter: AND WHAT ABOUT THOSE HARD DRIVES WITH THE HUNDREDS OF PHOTOS OF OTHER WOMEN? O'LEARY WASN'T WILLING TO DISCUSS ANYTHING THAT HE HAD NOT PLED GUILTY TO .>>\ YEAH, I WON'T TELL YOU ABOUT \ ANY OTHER CASES .>> Reporter: EVEN BEHIND BARS, O'LEARY WASN'T DONE TORMENTING WOMEN. BEFORE THE INTERVIEW ENDED, HE HAD A SPECIAL MESSAGE FOR DETECTIVE GALBRAITH .>>\ HI, STACY GALBRAITH .\ BET YOU WISH YOU COULD HAVE \ SHOT ME .>> HUH .>> Reporter: WAS IT UNNERVING ?>> YEAH. I DIDN'T... I DIDN'T SLEEP WELL THAT NIGHT .>> Reporter: IT WOULDN'T BE THE LAST SLEEPLESS NIGHT .>> WE DISCOVERED ANOTHER VICTIM .>> Reporter: BUT WHAT HAPPENED TO THAT WOMAN WAS FAR WORSE THAN THE DETECTIVES COULD IMAGINE .(\ DISTANT SIRENS BLARING \)>> Reporter: AMONG THE HUNDREDS OF PHOTOS FOUND IN MARC O'LEARY'S HOME, A PICTURE OF A YOUNG WOMAN BOUND AND GAGGED STOOD OUT .>> IN THAT CASE, HE ACTUALLY PHOTOGRAPHED HER, LIKE HE'D DONE OUR OTHER VICTIMS. BUT HE THOUGHTFULLY PHOTOGRAPHED HER WITH HER DRIVER'S LICENSE ON HER .>> Reporter: SO, YOU KNEW EXACTLY WHO SHE WAS .>> YES .>> Reporter: SHE WAS AN 18- YEAR- OLD WOMAN WHOSE IDENTITY WE ARE NOT REVEALING, LIVING JUST OUTSIDE SEATTLE IN LYNNWOOD, WASHINGTON. AND DID YOU CONTACT THAT POLICE DEPARTMENT IN WASHINGTON ?>> OH, RIGHT AWAY .>> Reporter: IT TURNS OUT THEY KNEW ABOUT HER. THEY EVEN HAD A RAPE REPORT FROM 2008-- ONLY, THEY BELIEVED IT WAS A FALSE REPORT. LYNWOOD POLICE DEPARTMENT

>> SHE REPORTED THAT SHE WOKE UP TO FIND AN INTRUDER IN HER BEDROOM, STANDING AT THE DOORWAY. HE WAS ARMED WITH A KNIFE. HE APPROACHED HER, BOUND HER HANDS BEHIND HER BACK, GAGGED HER, BLINDFOLDED HER, HAD HER ROLL OVER, AND THEN HE RAPED HER FOR A PERIOD OF TIME .>> Reporter: BUT DURING THE INVESTIGATION, THEY BEGAN TO DOUBT THE YOUNG WOMAN'S TRUTHFULNESS. ONE DETECTIVE EVEN THREATENED TO CHARGE HER IF SHE WAS LYING. THE YOUNG WOMAN GAVE AN INTERVIEW TO N. P. R. 'S " THIS AMERICAN LIFE .">> HE TOLD ME THAT IF I TOOK A LIE DETECTOR TEST AND IT CAME BACK THAT I WAS LYING, THAT HE WAS GOING TO TAKE ME TO JAIL HIMSELF .>> Reporter: AFTER THAT, SHE QUICKLY CHANGED HER STORY .>> SHE SAYS THAT SHE THOUGHT SHE MAY HAVE DREAMED THAT THIS OCCURRED. AND, AT ONE POINT, SHE SAID THAT IT DIDN'T HAPPEN. AND ULTIMATELY, SHE WAS GIVEN A CITATION FOR FALSE REPORTING .>> Reporter: SHE WAS FORCED TO PAY A $ 500 FINE AND PLEAD GUILTY FOR LYING ABOUT BEING RAPED. DETECTIVE GALBRAITH COULDN'T BELIEVE WHAT SHE WAS READING .>> I ACTUALLY FELT EMOTIONAL. I KNEW THAT WAS WRONG BECAUSE I COULD PROVE THEIR CASE NOW .>> Reporter: AND WHAT WAS THEIR RESPONSE WHEN YOU CALLED AND SAID, " HEY, YOU KNOW THAT CASE OF THAT YOUNG WOMAN WHO YOU THOUGHT WAS LYING AND YOU CHARGED HER? GUESS WHAT? I GOT A PICTURE OF HER AFTER SHE'S ASSAULTED FROM THE ACTUAL RAPIST ." >> THEY CAME OUT IMMEDIATELY .>> I WAS STUNNED. IT'S AN ABSOLUTE NIGHTMARE. EVERYTHING THAT SHE TOLD US WAS THE ABSOLUTE TRUTH. SHE WAS ISOLATED, ALONE, AND THEN NOBODY BELIEVED HER. THAT'S A LOT TO DIGEST .>> Reporter: THE COMMANDER AND HIS TEAM HEADED STRAIGHT TO THE YOUNG WOMAN'S HOME. THREE YEARS HAD PASSED SINCE SHE HAD REPORTED HER RAPE .>> SHE WAS VERY SURPRISED TO SEE US, AND WE TOLD HER WHAT WE HAD LEARNED. SHE WAS STUNNED. SHE WAS QUIET AT FIRST. SHE BEGAN TO CRY. IT WAS HEART- WRENCHING TO KNOW THAT SHE HAD LIVED WITH THIS ALONE FOR ALL THOSE YEARS .>> Reporter: THE WOMAN'S CHARGE WAS EXPUNGED FROM HER RECORD, HER FINE WAS REIMBURSED, AND SHE EVENTUALLY SETTLED A LAWSUIT WITH THE POLICE DEPARTMENT FOR $ 150, 000 .>> WELL, WE LEARNED MANY LESSONS HERE AT THE LYNNWOOD POLICE DEPARTMENT ON THE HEELS OF THIS INVESTIGATION. WE HAD OUTSIDE GROUPS COME IN TO TEACH OFFICERS AND DETECTIVES WAYS TO INVESTIGATE SEXUAL ASSAULTS. NOT EVERY VICTIM OF A VIOLENT CRIME REPORTS IT IN THE SAME WAY. AND THAT WE NEED TO UNDERSTAND THAT, AS STRANGE AS SOME CIRCUMSTANCES SEEM, THEY CAN BE TRUE .>> Reporter: IT'S AN OBSERVATION NOT GONE UNNOTICED BY THE RAPIST HIMSELF .>> IF WASHINGTON HAD JUST PAID ATTENTION A LITTLE BIT MORE, YOU KNOW, THEY'D PROBABLY... I PROBABLY WOULD HAVE BEEN A PERSON OF INTEREST, YOU KNOW, EARLIER ON .>> Reporter: O'LEARY WAS CHARGED WITH THAT WOMAN'S RAPE AND YET ANOTHER, SIMILAR SEXUAL ASSAULT IN WASHINGTON. HE PLED GUILTY IN BOTH CASES, BRINGING THE KNOWN NUMBER OF VICTIMS TO SIX. BUT STACY AND EDNA BELIEVE IT DOESN'T STOP THERE .>> OH, YEAH .>> ABSOLUTELY, THERE'S MORE .>> Reporter: O'LEARY HAD ENCRYPTED COMPUTERS THAT INVESTIGATORS ARE STILL UNABLE TO OPEN .>> IT WENT TO QUANTICO. IT WENT TO THE F. B. I. LAB HERE .>> Reporter: NOBODY CAN GET INTO IT ?>> NOBODY CAN GET INTO IT. AND I WAS TOLD THAT PROBABLY NO ONE EVER WILL .>> Reporter: ALL OF THIS BEGS THE QUESTION, IF MARC O'LEARY WAS WILLING TO GIVE SUCH EXPLICIT DETAILS ABOUT THE TERRIBLE CRIMES THEY ALREADY KNEW HE HAD COMMITTED, WHAT POSSIBLE HORRIFIC THINGS WAS HE STILL HIDING ON THOSE HARD DRIVES? YOU THINK IT'S WORSE ?>> DON'T KNOW. THE OTHER THING WE WONDER IS, COULD SOMEONE ELSE HAVE BEEN INVOLVED ?>> Reporter: EX- GIRLFRIEND AMY WONDERS THE SAME THING .>> IT SOUNDS TO ME LIKE MAYBE HE'S PROTECTING SOMEBODY ELSE, IF HE'S WILLING TO 'FESS UP TO EVERYTHING THAT HE'S DONE BUT HE'S NOT WILLING TO TURN OVER ALL OF THE INFORMATION THAT HE HAS .>> Reporter: BUT MARY IS HOPING OTHER VICTIMS OF O'LEARY'S WILL COME FORWARD .>> WELL, I THINK THE BIG THING IS JUST THAT RAPE VICTIMS DON'T HAVE TO BE ASHAMED. HE KEPT GETTING AWAY WITH IT, AND HE WANTED TO DO IT AGAIN. AND EACH TIME HE DID IT, HE GOT A LITTLE MORE COCKY ABOUT WHAT HE WAS DOING AND A LITTLE MORE DANGEROUS .>> Reporter: AND THERE'S NO FEAR IN YOUR LIFE NOW, ASSOCIATED WITH IT ?>> NO. I WON'T LET IT HAPPEN. I WON'T LET HIM INSTILL FEAR IN ME. NO, I DON'T WANT ANYBODY TO DO THAT TO ME .>> Reporter: HER STRENGTH FUELS THE WORK THAT EDNA AND STACY HAVE COMMITTED THEIR LIVES TO. HE'S ONLY BEHIND BARS BECAUSE OF THE WORK THAT YOU DID TOGETHER .>> RIGHT. BUT IT'S NOT TWO PEOPLE, RIGHT? IT'S NOT... IT'S NOT THREE PEOPLE, WITH JOHNNY INVOLVED. IT'S A WHOLE GROUP. IT TOOK THE ENTIRE GROUP .>> KNOWING THAT YOU PULLED SOMEONE LIKE THAT, SO HORRIBLE, OUT OF SOCIETY SO THAT HE CAN'T HURT ANYONE AGAIN, IT WAS VERY, VERY REWARDING. THIS IS WHY I DO THIS .>> JAKE NOLAN SET OUT TO THEOFFICE AND HOME OF DR. MICHAELWEISS. JAKE HAD WITH HIM A DUFFEL BAGWITH A MASSIVE SLEDGEHAMMER, ASTEAK KNIFE AND ZIP TIES .>> I INTENDED TO KILL HIM .>> WHY ?>> I SAW JAKE NOLAN BRAINWASHEDBY DR. PAMELA BOOKBINDER, AN IVYLEAGUE- TRAINED PSYCHIATRIST. SHE WAS BRILLIANT .>> BY THE END OF THISMANIPULATION, JAKE NOLAN HADBECOME WEAPONIZED .>> AND I OBEY JUST LIKE APUPPET. I'LL KILL FOR THIS WOMAN .>> SHE SACRIFICED HIM .>> DR. BOOKBINDER CLAIMS THAT SHE HAD NO INVOLVEMENT AT ALL IN THIS. I MEAN, WHO WOULD POSSIBLY SNAPA SELFIE RIGHT AFTER THEY TRIEDTO MURDER SOMEONE ?>>\ CBS NEWS, ORIGINAL REPORTING.