DENVER -- A cousin of a suspected serial killer said Scott Kimball knows where the bodies of the victims are buried, and if the FBI wants to know, they may have to make a deal.

The claim comes from Ed Coet, Kimball's cousin.

The FBI has been actively looking at Scott Kimball as a possible suspect in the disappearance and presumed murders of four people dating back to early 2003 -- Terry Kimball, his uncle, Lee Ann Emery, Jennifer Marcum, and Kaysi McLeod.

But after talking with Kimball for hours this week, Coet said his cousin is waiting for the right offer from investigators.

"I have no doubt that Scott knows what happened," Coet said Thursday from his brother's Commerce City home. "(Kimball) knows the girls are dead. He's as much as told me that. He knows who did it. He knows where they're buried. He knows how it happened, when it happened, why it happened. But he didn't do it."

Coet also said Kimball told him of another missing Colorado girl that may have been buried in the high-country in the late 1970s or early 1980s.

An FBI spokeswoman said bureau agents are aware of the claim and are looking into it.

Based on court records, this would not be the first time Kimball, a convicted con man with a long history of lying and stealing from people, has claimed to have inside information of someone else's crime while he himself faced pressure from investigators. But his cousin said it's far too early to forget about the concept of innocent until proven guilty.

"And if there were charges that could be brought, they would've been brought," Coet said. "So I have an interest in saying that he deserves to have that presumption."

McLeod's told 7NEWS they are not surprised to hear Kimball is still trying to make a deal.

Kimball sits in the Park County jail, awaiting another federal prison sentence, this time as a felon in possession of a gun.

"He's a bad hombre. He's also a bad person. OK? There's no disputing that ... but he wants people to know that there's another side to this story. And his side has not yet been told," Coet said.