KUSA – The wife of a man under investigation by the FBI for the disappearance of four people says she has no doubt her husband is a serial killer.

Kaysi McLeod, Leann Emry, Jennifer Marcum and Terry Kimball each went missing after spending time with Scott Kimball in 2003 and 2004. Terry Kimball was Scott Kimball's uncle.

The families of Emry, Marcum and McLeod say there is no doubt in their mind Kimball murdered their loved ones, and they believe there are more victims.

McLeod's mother and Kimball's wife, Lori McLeod-Offerson, says she was nearby during an incident where she believes Kimball tried to kill his son.

"There was a steel storm gate out at our house and it fell on top of him. (His son) Justin said his dad pushed it on him when he came out of his coma a month later," McLeod-Offerson told 9NEWS Friday.

She claims Kimball then put his son in the car and while taking him to the hospital, he somehow fell out of the window.

"Scott told me Justin was reaching to roll the window down," said McLeod-Offerson, who says Kimball told her that her son instead reached the door handle and fell out.

"Justin told everybody: 'I did not reach for the window. Dad reached over, opened the door and pushed me out,'" said McLeod-Offerson. "He says he remembered Scott's hand on his face pushing him."

McLeod-Offerson is still married to Kimball but says she is seeking an annulment. She says she feels Kimball tricked her.

"Everybody loved him, my family loved him, my friends love him, very charismatic," said McLeod-Offerson. "After Kaysi went missing he told me she was probably just running and wanted time to herself."

"I believed I could trust him and he wanted a real normal life and I felt I could offer that to him. He's not who he is," she said.

An affidavit obtained by 9Wants to Know shows the FBI is investigating Kimball in the disappearances of the four people.

The FBI has identified one of four previouslyunidentified women thought to be connected to the Scott Kimball case. She is known to be fine and the FBI does not believe she is connected to any of the women who have disappeared. The FBI still wants the public's help in finding three other women.

Click here to see the pictures of all the missing people linked to Kimball.

"We really believe that these four women are going to be in the position to tell us some very important things about the investigation," said FBI Special Agent in Charge of the Denver Division James Davis. "These are four people we can't identify and based on these photos and the facts surrounding the photograph we think they are important to us."

If you have any information on Kimball or the people in the pictures, call the Denver FBI office at 303-629-7171.