In a bid to resolve a series of unsolved cold cases, authorities are searching a Kansas property that once belonged to a Dennis Rader, the self-dubbed “BTK Killer” who admitted to murdering 10 people between the 1970s and 1990s.

The efforts in Park City began this week, nearly a decade after Rader’s arrest in 2005. He is currently serving out 10 life sentences at El Dorado Correctional Facility, but authorities believe Rader may have killed more people before he was finally caught.

“Our investigation has led to additional unsolved murders and missing persons that are possibly connected to BTK,” Osage County Undersheriff Gary Upston told NBC News Wednesday.

Upston noted the new search efforts were sparked by a “possible connection” with the disappearance of Cynthia Kinney, a 16-year-old high school cheerleader who was reported missing from Oklahoma in 1976. She was last seen leaving a laundromat.

The El Dorado Correctional Facility in El Dorado, Kansas.

For years, Rader — a dedicated churchgoer and married father of two — evaded law enforcement. It inspired him to mail out cryptic letters to the media and investigators, a practice that eventually culminated in his capture. Police were able to trace a floppy disk he mailed to a local TV station to a computer at his church. From there, investigators determined Rader’s DNA matched that of the killer.

In one of his many notes, Rader said that he should be called “BTK,” which is short for “bind, torture, kill.” He pleaded guilty in June 2005 to 10 murders that occured in Wichita and Park City from 1974 to 1991.

A family walks in the street in front of the house that Dennis Rader lives in February 26, 2005 in Park City, Kansas.

During his trial, Rader described a double life, explaining to the court that he was a church congregation president and Boy Scout leader who also had violent rape fantasies and “hit kits,” his term for bags packed with items like rubber gloves, rope, tape, and handcuffs. He also said he would choose his victims and then stalk them before killing them.

In more than one instance, the killer claimed he took Polaroid photos of the people he murdered.

Rader lived at the site, which is now an empty field, with his family for nearly two years. Two of the murders he admitted to happened in the area, the Wichita Eagle reported. The house was torn down in 2007, shortly after his arrest.