Overland Park ? The pastor of the Wichita church where Dennis Rader was a longtime leader believes a “demonic force” drove Rader to become a serial killer.

The Rev. Michael Clark, pastor of Christ Lutheran Church in Wichita, talked about his experiences with Rader during an appearance Sunday at Holy Cross Lutheran Church in Overland Park.

Rader, who lived in the Wichita suburb of Park City, pleaded guilty in June to killing 10 people between 1974 and 1991. He was sentenced in August to 10 consecutive life prison terms.

The killer who terrorized the Wichita area for years became known as BTK, a nickname he gave himself in letters to police and the media. The initials stood for “Bind, Torture, Kill.”

After long silence, the communications resumed in March 2004, when a letter to The Wichita Eagle gave details of a 1986 death not previously linked to the serial killer. Included with the later was a photocopy of the slain women’s driver’s license and photos of her body.

Rader had long been active at Christ Lutheran Church, serving on its council and becoming president of its board not long before his arrest. A floppy disk sent to a Wichita television station by the BTK killer was traced to the church through an electronic imprint, and detectives went there with a search warrant, trying to find out who had access to the church computer.

“Dennis was influenced, I believe, by some kind of demonic force and that played a role in the choices and decisions he made,” the Wichita pastor told members of the suburban Kansas City congregation.

Clark said being possessed doesn’t mean Rader is some type of monster but that there was something inside him that drove him to kill. Rader even recognized that, Clark said, pointing to references in some of his letters to a monster inside him that he couldn’t control.

Clark said that a year ago he would have chased anyone suggesting that demonic possession was possible out of his office. He said he did not believe in that, regarding Satan as the “personification of evil of the human condition.”

But his experience with Rader changed his views.

Clark said Rader’s evil was felt not only by his victims and their families but by Rader’s own family, his congregation, and the people who knew him.

“There were and still are a lot of people still in pain. There is no question about that,” Clark said.

Asked why God would let Rader prey on victims and cause of much pain, Clark said God gives people the free will to make choices.

“There are times where demonics enter our mind and our soul, which causes us to make bad decisions,” he said.