Oklahoma sheriff’s deputies were at the site of the former home of the BTK serial killer in Kansas on Tuesday looking for possible leads on unsolved cases that could be related to the convicted killer.

Dennis Rader was sentenced to 10 consecutive life sentences in 2005 after terrorizing Wichita and his home in the suburb of Park City between 1974 to 1991, giving himself the nickname BTK, which stood for bind, torture, and kill.

“The Osage County Sheriff’s Office is continuing to follow leads in unsolved missing persons and murder cases possibly related to BTK,” Undersheriff Gary Upton told the Wichita Eagle.

Upton declined to say wha investigators were looking for.

“We’re just investigating some leads that took us to that location,” he said. “I can’t comment any further.”

Upton said investigators were digging at Rader’s old property, which is now owned by the city, KWCH reported.

Authorities in Osage County told KAKE that the investigators were acting on a tip about the disappearance of Cynthia Kinney, who vanished at 16 in 1976 and has never been located. KOKI reported in February that Osage County investigators had interviewed Rader, now 78, about a cold case, and Rader himself said he’d been interviewed twice about the Kinney case.

For the latest true crime and justice news, subscribe to the ‘Crime Stories with Nancy Grace’ podcast.

[Featured image: Dennis Rader in 2013/Kansas Department of Corrections]