Updated

The son of a U.S. Census Bureau worker found hanging from a tree in eastern Kentucky with the word "fed" scrawled on his chest said Tuesday he has no doubt his father was murdered.

Josh Sparkman told The Associated Press in a phone interview that he is frustrated investigators have not ruled out suicide or accidental death.

"I look at it as disrespectful to be still throwing suicide and accident around," he said. "He didn't do this to himself. That's dishonorable. My dad was a good man. No person on this planet is going to fight cancer like he did, then turn around and kill himself a year or so later."

Bill Sparkman, 51, was a substitute teacher and part-time census worker whose body was found tied to a tree with a rope around his neck in a remote Appalachian forest earlier this month. The Clay County coroner said "fed" was written on his chest, apparently in felt tip pen.

An Ohio man who found the body while visiting a cemetery said Sparkman had been gagged and his hands and feet were bound with duct tape. Authorities have refused to say if he was going door-to-door for census surveys before he died.

Josh Sparkman, 19, said he learned of his father's death Sept. 13, a day after his body was found. Bill Sparkman adopted him when he was a baby.

"I completely broke down," Josh Sparkman said. "It's always just been me and my dad. It's all I have, and I don't have him anymore. I'm just kind of by myself."

Jay Blanton, a spokesman for Kentucky Gov. Steve Beshear, said the governor is confident state police are moving as quickly as possible.

"The governor certainly understands the concerns and feelings of the family during a terrible tragedy like this one," Blanton said. "But at the same time he's very sensitive to the fact that there's an ongoing investigation and that while it needs to proceed expeditiously, it also needs to be done the right way and comprehensively."

Josh Sparkman said police and the FBI have searched his father's home but told him little — even when the body would be released. He has advised authorities that his father wanted to be cremated.

He said he moved to London, Ky., before he started kindergarten so his father could get a job with the Boy Scouts. Although he had been living lately with friends in Tennessee, he spent most of his childhood in his father's small ranch home in London.

He said he is broke now, with just $20 to his name, and doesn't know how he is going to pay for a funeral or the $600-a-month mortgage on his father's home. He has decided to move back to London and was applying for jobs Tuesday.

Shirley Allen, Bill Sparkman's neighbor, said Josh Sparkman visited her two days after the body was found.

"I just asked him, 'Are these rumors true that your dad is dead?"' she said. "He said, 'Yes,' but he didn't know a thing."