"The bottom line: BTK is arrested," Wichita Police Chief Norman Williams said at a news conference in Wichita with some of the victims' family members.
BTK investigator Lt. Ken Landwehr identified the suspect as Dennis Rader, a 59-year-old city worker in nearby Park City, who was arrested Friday at his suburban home.
The BTK killer a self-coined nickname that stands for "Bind, Torture, Kill" had been linked to eight killings committed between 1974 and 1986. Police said Saturday they have attributed two more slayings to BTK, from 1985 and 1991.
No charges had been filed Saturday. Prosecutor Nola Foulston said that while there is no statute of limitations for homicide, the death penalty would not apply to any crime committed before 1994, when the death penalty was introduced in Kansas.
BTK sent letters to media about the crimes in the 1970s, but stopped for more than two decades before re-establishing contact last March with a letter about an unsolved 1986 killing.
Since then, authorities said the killer has sent at least eight letters to the media or police, including three packages containing jewelry that police believed may have been taken from BTK's victims. One letter contained the driver's license of victim Nancy Fox.
CBS News Correspondent Cynthia Bowers reports the killer teased police with cryptic clues that may be true or not: that he was born in 1939, raised by a widowed mother and is obsessed with railroads. Just last week, three packages were sent to a local TV station containing jewelry that could be from a victim.
The new letters sent chills through Wichita, but also rekindled hope that modern forensic science could find some clue that would finally lead police to a killer most thought was dead or safely locked in prison for some other crime.
Thousands of tips poured in, and the Kansas Bureau of Investigation conducted hundreds of DNA swabs in connection with the BTK investigation.
A source with knowledge of the investigation who spoke on condition of anonymity said surveillance gave police their "first big piece" of recent evidence, leading authorities to a vehicle and the suspect.
One of the victims newly identified by police, 53-year-old Marine Hedge, lived on Rader's street in Park City. She was abducted from her home in 1985, and her body was found eight days later along a dirt road.
Investigators searched Rader's house Friday and seized computer equipment.
"This has not been an easy task," Wichita Mayor Carlos Mayans said Saturday. "Our fine police department has been, at times, questioned. Their competence was questioned, and their actions were often second-guessed.
"But all the while, these officers were steadfast in their commitment to solve the biggest police case in Wichita's history," Mayans said.
The BTK slayings began in 1974 with the strangulations of Joseph Otero, 38, his wife, Julie, 34, and their two children.
The letters began that same year, with poems and graphic descriptions of the crimes. The killer even called police with details of Nancy Fox's 1977 slaying.
When one of his messages, a poem sent to The Wichita Eagle-Beacon in 1978, was mistakenly routed to the classified ads department, BTK sent a letter to KAKE-TV days later complaining: "How many do I have to kill before I get my name in the paper or some national attention?"
Another letter to the newspaper also underscored BTK's need for recognition.
"How about some name for me, its time: 7 down and many more to go," it read in part. "I like the following. How about you? 'THE B.T.K STRANGLER, 'WICHITA STRANGLER', 'POETIC STRANGLER', 'THE BONDAGE STRANGER' OR 'PSYCHO', 'THE WICHITA HANGMAN', 'THE WICHITA EXECUTIONER,' 'THE GAROTE PHATHOM', 'THE ASPHYXIATER'."
The letters stopped in the late 1970s, but picked up last March, when a letter arrived at The Wichita Eagle with information on an unsolved 1986 killing, a copy of the victim's driver's license and photos of her slain body.
The return address on the letter said it was from Bill Thomas Killman initials BTK. The address appeared to refer to a now-vacant building.
Police have been extremely tight-lipped about the case in the past year.
In December, the arrest of a Wichita resident on minor charges sparked widespread speculation of a possible link to BTK. That man, who had no connection to the case, later filed a defamation lawsuit against media outlets.