WICHITA, Kansas -- So what do we know about suspect Dennis Rader? We have been gathering a mass of information on his background.

Most interesting, we will hear from Dennis Rader himself. He spoke to KSN News on a general news story back in 2001. It was a surprise to us, and with what police have said Saturday, Rader’s life is a surprise to the entire city.

Dennis Rader, the man now thought to be BTK, allegedly fooled police for decades. Now scores of Kansans are learning that he apparently fooled them as well.

"It’s the biggest shock I’d ever had -- the nicest guy in the world. I’d have given him a key to watch my dog if I had to when I was leaving town," said Gary Van Dusen, neighbor.

Rader was a churchgoer at Christ Lutheran Church in north Wichita. He was not just any member of the church, he was president of the Congregation Council.

"It’s consistent with what we had thought all along, that it’s an individual who blends well into the community, was basically invisible to his neighbors and friends and coworkers because he was just an ordinary guy," said Arlyn Smith, former BTK investigator.

Rader was a compliance officer in Park City. Residents knew him as a stickler for detail.

"He’d harass you for your grass being six inches tall, or something like that," said one neighbor.

But Rader also handled animal control. KSN News interviewed him about a story on animal attacks in Park City.

Business reference books dating back to the 1970’s show Dennis Rader as an ADT security technician. That’s key, since police have often thought BTK gained access to homes as a utility employee.

We also know that Rader has a long history with Wichita State University. That matches what police have thought all along about the BTK killer.

An alumni book shows Rader graduated WSU in the late 1970’s. Police linked a BTK letter to a school copy machine and the brother of victim Kathryn Bright reports BTK asked him if he’d seen him around campus.See video story on KSN.comMore BTK-related stories and video on KSN.com