Dennis Rader is listed as a municipal worker in Park City
Dennis Rader was arrested without incident in Park City on Friday and is now suspected of committing 10 murders, police in nearby Wichita said.
Charges are yet to be brought in the case, which had been thought to consist of eight murders from 1974 to 1986.
"The bottom line: BTK is arrested," Police Chief Norman Williams told a news conference where he was applauded.
The suspect's DNA has been linked to at least one murder, officials said.
Tips from public
BTK resurfaced last year when a claim was made for an eighth victim.
SUSPECTED BTK VICTIMS Marine Hedge, 53 Delores "Dee" Davis, 62 Joseph Otero, 38, his wife, Julie, 34, and their two children Kathryn Bright, 21 Shirley Vian, 24 Nancy Fox, 25 Vicki Wegerle, 28 (pictured)
Killer's reign of terror
The Wichita Eagle newspaper received a letter in March enclosing photos and a copy of a driver's licence of Vicki Wegerle, whose 1986 murder was never solved.
Other letters to media and police followed, some including jewellery that police believed may have been taken from BTK victims.
Tips from the public began to pour in and Kansas police took hundreds of DNA samples.
Families of BTK victims and Kansas government officials also attended Saturday's news conference where the arrest was announced.
Additional victims
Chief Williams said that work on the case had brought the victim toll to 10.
The two additional victims were named as Marine Hedge, 53, and Delores "Dee" Davis, 62.
Mayor Carlos Mayans said police had phoned him late on Friday evening to say the DNA of the suspect matched evidence gathered from the scene of at least one BTK murder.
It had, he said, been a "long journey" and he put the arrest down to "diligence, tenacity, determination and just plain good police work".
The BTK killer coined his own nickname in letters claiming the murders.
Most of the victims were women killed in their homes but the first murder attributed to the BTK killer was that of an entire family in January 1974: Joseph Otero, 38, his wife, Julie, 34, and their two children.
Mr Rader is listed by Park City's website as a compliance supervisor, dealing with such things as animal control and broken-down cars.
Wichita Police today arrested Dennis Rader, who is suspected of being the BTK killer. BTK, an acronym for "Bind, torture, kill," was the name the serial killer gave himself after killing eight people between 1974 and 1986 in that manner. The killer was thought to have disappeared for 25 years before he resurfaced in March of 2004. He was later linked to two unsolved murders, which took place in 1985 and 1991. Police Chief Norman Williams publicly announced the guilt of Mr. Rader prior to any trial preparations when he said to reporters ''"The bottom line, BTK is arrested."''

The commander of the task force investigating the BTK killings, Lt. Ken Landwehr, said Rader had been arrested after being pulled over in a routine traffic stop. Authorities had questioned a ''"person of interest"'' Friday, which led them to a Park City home just outside Wichita and eventually to the identity of BTK.

BTK was notorious not only for his brutal way of killing people, but for taunting police and other investigators with letters throughout his 12-year killing spree. Investigators had run out of leads until police received a letter from BTK in March of last year.

Police have said they charge Rader with eight counts of first-degree murder and two other homicide charges. According to CNN, police were able to use Rader's daughter's DNA to find Rader. DNA of close family members has been used in a few previous cases to identify suspects, through a new technique known as  familial searching.