"I have dreams often that she's coming home, and that we're playing, and the dreams are as vivid as they are real," says Steve.
"I believe she's just a beautiful young lady, 7 years old," says Marlene. "She's not a baby anymore."
They've tried to rebuild their lives, but Marlene says, "We are as happy as we can be until she comes home. … We will be an ecstatic family when we're all together like we should be."
For the Aisenbergs, the ordeal began in Valrico, Fla., just outside of Tampa. On the morning of Nov. 24, 1997, at 6:30 a.m., Marlene noticed that something had gone terribly wrong.
"It's the most horrific thing you can imagine, looking into your child's crib and not seeing her there," says Marlene. "There is just nothing to describe it, and I remember just screaming, 'Steve' and calling 911."
Marlene and Steve would like to forget everything about that awful night, especially the garage door that they admit leaving open. That night, with the door open, the Aisenbergs can only assume that someone crept quietly into the house and snatched Sabrina while they were sleeping.
After Marlene called 911, Steve went next door to his neighbor, former Tampa cop Scott Middleton. Immediately, Middleton's police training kicked in: "I'm a parent myself. There just wasn't any emotion to say, 'My kids are gone.'"
But, as Correspondent Troy Roberts reports, it was just the beginning of the nightmare for the Aisenbergs, whose behavior was being examined and analyzed.
"There was no emotion," says Middleton. "There was absolutely no emotion with Steve and Marlene, like nothing had happened. They weren't broken up, no tears being shed."
But news video shows how distraught Marlene was the morning Sabrina disappeared: "I didn't understand anything that was going on, I was in hysterics."
Within minutes of receiving a call, deputies from the Hillsborough County Sheriff's Department descended on the Aisenberg home and the media was right behind them.
"This was the lead story in our newscast everyday for months, because everyday there was something new to tell," says reporter Bill McGinty, who covered the story for WTSP, the CBS affiliate in Tampa.
Sheriff's deputies began an extensive search in and around the Aisenberg home, but found nothing. Deputies were struck by the chaotic nature of the Aisenberg home. To the cops, it spelled neglect. But to her friends, it was just the way Marlene was.
"She was not an immaculate housekeeper," says her friend, Kathy Dotson. "Anybody would attest to that, that her house was a mess."
By the end of that first horrible day, police encouraged Steve and Marlene to go on television and plead for their daughter's safe return. But to a curious public, the Aisenbergs seemed cold and aloof.
"You're in shock, and I don't wish anybody having to step into my shoes. My baby is gone. I have no idea where she is and I have to say something," says Marlene. "You don't know what to say, you don't know how to react. There's not a book you can read on what to go through when you've had something horrible happen in your life."
Everything was going against the Aisenbergs. For instance, there was a snippet of videotape that showed, for a brief moment, Steve with a smile on his face. "A lot of our behavior was what was dictated for us to do and be by the police," says Steve. "When we were leaving the house one day, they made a joke and we laughed."
"The focus of the story shifted from Sabrina Aisenberg, 5-month-old missing baby, to Marlene and Steve Aisenberg," says McGinty.
Even Brownie, the family dog, came under scrutiny. Why had he not barked at the intruder? "Brownie barked at everybody," says Middleton. "She just always barked. She was a noisy dog. I don't ever remember her being quiet."
With permission from the Aisenbergs, the FBI tapped their phone so that any call from a kidnapper could be traced. One of the first calls was from Steve's brother, Dave, a lawyer, who warned Steve to be wary of the police.
When detectives listened in, they were amazed that Steve, supposedly awaiting a call from his child's kidnappers, never answers the call-waiting beep that kicks in -- not once, but twice
To the police, this was proof that the Aisenbergs knew much more about their baby's disappearance than they were saying. Any other concerned parent would have cleared that line immediately. Suspicious, they confronted Marlene, who said they told her they believed she knew where Sabrina was – or what had happened to her. "We called them here to help us find her, or who took her," says Marlene. "Where is she?"
Twenty-four hours after Sabrina was reported missing, the Aisenbergs were frustrated with the police response. They say police ignored tips about possible Sabrina sightings.
"They tried to find a body," says Marlene.
"The investigators never really got past Mr. and Mrs. Aisenberg," says Graham Brink, a reporter for the St. Petersburg Times. He's written extensively about the case. "In their minds, they could never rule them out as prime suspects."
"Don't investigate us at the exclusion of looking for our baby," says Steve.
Before Sabrina disappeared, life for the Aisenbergs largely revolved around their three children: Sabrina and her two older siblings, William, then 9, and Monica, then 5.
Marlene even started her own business for kids, running a baby and toddler exercise program. Steve worked real estate in Tampa's booming economy.
But ugly gossip was spreading. Meanwhile, the Aisenbergs continued to cooperate with the investigation. Sheriff's detectives gave the Aisenbergs lie detector tests and then leaked information that some of Marlene's answers were "deceptive," even though Marlene says both tests were inconclusive.
The investigation was now three days old, and Steve heeded his brother's advice. He hired Barry Cohen, one of the most high-profile and combative lawyers in Florida.
Cohen says there is nothing that points to his clients' guilt, but he says detectives had one mission, to prove the Aisenbergs were involved. "When I saw the police were acting in bad faith and that they were destined to try to frame Marlene and Steve, that's when we stopped cooperating," says Cohen.
The Hillsborough County Sheriff's Office refused to talk to 48 Hours Mystery about the case, but McGinty says the cops definitely pursued other leads, even though the vast majority were from people who mistakenly thought they had spotted Sabrina.
"We went to their Aisenberg war room, where they had volumes of information, places they'd been to, thousands of different leads," says McGinty.
But there's no doubt the police felt stymied, just when they thought they were on the verge of breaking the couple. The police thought their best suspects were sitting at home, so in a highly unusual move, detectives got a warrant allowing them to secretly plant tiny listening devices called bugs in the Aisenberg's kitchen and bedroom.
"I think they thought it was their last chance of getting the Aisenbergs," says Brink. "The investigators didn't have any physical evidence at that point. They didn't have any eyewitness statements. They hadn't found Sabrina. There had been no ransom note."
48 Hours asked Mike Perros, a wiretap and bug detection expert, to come to the Aisenberg home to demonstrate how the wiretapping operation worked. He explained that the sound quality is excellent, as long as it's applied correctly.
Every day, for nearly three months, from 7 a.m. to midnight, sheriff deputies listened and recorded thousands of private conversations going on in the Aisenberg home.
Sabrina had only been gone for two months, but a federal grand jury was convened to examine her disappearance. The Aisenbergs were asked to testify, but Cohen advised them to invoke their Fifth Amendment rights. "I think we did what we felt was necessary at the time," says Steve. "We did what we were advised to do."
Cohen says he advised his clients not to testify because of the reputation of lead federal prosecutor Steven Kunz: "He has no business being in the system."
As the grand jury heard testimony, social services workers showed up at the Aisenberg's front door to investigate whether the couple's older children, William and Monica, were being mistreated.
"We were furious," says Marlene. "I think they wanted to scare us and let us think that they were taking away our children."
But it was just the beginning of the Aisenberg's ordeal.
As in the JonBenet Ramsey case, detectives looking for Sabrina were convinced the parents were somehow involved.
"I think once law enforcement collectively decided that the Aisenbergs were responsible and guilty, then whatever it took to implicate and to charge them, that was going to be done," says John Fitzgibbons, a former U.S. attorney now in private practice in Tampa.
Meanwhile, the Aisenbergs were trying to keep their hopes alive. "What I think about is how can I bring my daughter home," asks Steve.
By May 1999, the Aisenbergs were struggling financially, so they sold their house in Florida and moved back to Steve's childhood home in Bethesda, Md.
Just four months later, on Sept. 9, Marlene received some unexpected visitors at home. Frantic, she called Cohen. "They're in the house. They've broken into the house," recalls Marlene. "There's a gun being pointed right at my face. It was the most horrifying thing other than waking up and finding my daughter not in her crib."
The intruders told Marlene they were the FBI. At the same time, agents were arresting Steve across town. He says they put him in a cell, strip-searched him, and took fingerprints and photos.
Marlene and Steve were later released on bail, using Steve's father's home as collateral. The Aisenbergs were indicted for conspiracy and for lying to investigators, not for murder. The charges, if proved, could send them to prison for up to 30 years.
The indictment is based on the secret police bugging operation that lasted nearly three months. Those bugs recorded more than 2,600 conversations between the Aisenbergs in which police say they discussed killing their daughter.
Prosecutors say these taped conversations proved that Steve had killed their daughter.
"I thought, 'The government has a hell of a powerful case here,'" says Fitzgibbons.
At the couple's bail hearing, a federal prosecutor told a judge she had heard Steve on tape saying, "I wish I hadn't harmed her. It was the cocaine."
"I'll do drug tests from now to eternity, and you'll never find any drugs in my system," adds Steve. "I never said anything that they say I said. Marlene never said anything that they said she said."
But do the tapes contain a confession, or will they just add to the confusion already surrounding the case?
It's been more than two years since Sabrina vanished from her crib. And federal prosecutors were sure they had a case, not a murder case, but a case of conspiracy.
In December 2000, the Aisenbergs were about to have their day in court. The audiotapes were the backbone of the prosecution's entire case. But people in the courtroom said it was very difficult to understand the tapes.
"I later described it as it sounding like chickens squawking with a hurricane playing in the background," says Brink. "It was just noise."
"All we could hear in the courtroom that day was mumbling. And you could hear the hum of appliances," adds McGinty. "When it was played in open court and the judge looked over at the prosecutor, and that look was a glare, 'This is the best you got?'"
Cohen hired a former analyst from the FBI to listen to the tapes. To combat Cohen's expert witness, Kunz hired celebrity private investigator Anthony Pellicano, whose clients included Michael Jackson and Liz Taylor.
Pellicano had a reputation for resorting to violence to get his way, and he later pleaded guilty to possessing illegal explosives. "Why would the government stoop to hiring Tony Pellicano, when shortly after that, he was indicted himself, and he's in federal prison today," asks Cohen.
It appeared that Pellicano and the prosecutors were the only ones in the courtroom who could hear the incriminating evidence and this came as no surprise to the Aisenberg team.
48 Hours hired its own audio expert, Jack Mitchell, to listen to the tapes. "It's almost as if it were just simply made up," says Mitchell, who has worked for the U.S. Department of Justice. "There is no evidence whatsoever on any of these recordings that I have examined that will implicate the Aisenbergs in the disappearance of Baby Sabrina. None."
Mitchell has analyzed hundreds of tapes during his career, and is convinced that some of these voices may not even belong to the Aisenbergs.
48 Hours also played the tape to Perros, who could not understand any of the evidence. "It sounds like they had some type of technical problem with the application," says Perros.
The damning evidence was nowhere to be found. "All lies, just all lies. We knew there was nothing on those tapes," says Marlene.
All of this was enough to make Cohen suspect the worst, that the Aisenbergs were framed. "They wanted a quick confession, clear this case, and look good," says Cohen. "But the only problem was they didn't have any facts, so they had to make them."
The prosecution's case against the couple began collapsing. Now, it was the feds who had some tough questions to answer.
In fact, two judges appointed to review the prosecution's case found the Aisenberg tapes were "largely unintelligible." They called some of the statements false, and pure fiction. In a stunning blow to the prosecution, the recordings were ruled inadmissible.
One week later, all charges were dropped.
After repeated calls to Kunz were not returned, 48 Hours approached him for answers. He refused to comment.
While it was a hollow victory for the Aisenbergs, they have never given up. Today, they hope a new clue will bring their daughter home.
To this day, the Aisenbergs keep a separate bedroom in their Maryland home reserved just for Sabrina, even buying her souvenirs from their vacations.
They believe Sabrina is somewhere alive and well, and is being raised by a family who desperately wanted a child. At times, Sabrina's return has seemed tantalizingly close.
But Marlene has good reason to never give up hope. In May 2003, a couple in Illinois began adoption proceedings on a 6-year-old child, Baby Paloma, who did not have a birth certificate. The Aisenbergs were hopeful, and Pontiac Police Chief Don Scholsser began an investigation.
A lot of people, including the Aisenbergs, believed the mystery behind Sabrina's disappearance was about to be solved. "It all just seemed like it was gonna fit, and that this could really be her," says Marlene. "We were on pins and needles, on edge, just praying it was gonna be her."
For two weeks, they waited for the results of a DNA analysis. But Paloma's DNA did not match. Paloma's natural mother was a Mexican woman who abandoned her baby at a clinic on the Texas border. A nurse at the clinic gave the baby to her sister in Illinois. Eventually, the sister adopted Paloma legally.
Are the Aisenbergs still angry? "If they bring Sabrina home, I won't be angry, and I have to pray that they will do the right thing, that they will look for her and bring her home," says Marlene.
These days, the Aisenbergs put their hope in those who've stood by them; the staff at the National Center for Missing and Exploited Children has been invaluable.
Joe Mullins is a forensic artist at the center who creates age-progressed photos of what children may look like years after they've gone missing. This technology has helped in the recovery of more than 500 children.
Using facial features from Sabrina's older brother and sister at about the same age, Mullins creates this image of what Sabrina might look like today at 7.
"I pray to God somebody can look at her and say, 'That's an Aisenberg,'" says Marlene. "I believe that she could herself see this picture, and she's old enough to say, 'Oh my God, this looks like me.'"