Updated

A Kentucky census worker found hanging from a tree with the word "fed" written on his chest killed himself and staged his death to look like a murder, authorities said Tuesday.

Kentucky State Police said Bill Sparkman died at the same location where his body was found Sept. 12 near a cemetery in a heavily wooded area of southeastern Kentucky.

A man who discovered the body in the Daniel Boone National Forest said the 51-year-old was bound with duct tape, gagged and had an identification badge taped to his neck.

Police told a news conference Tuesday that Sparkman was naked except for socks and had his glasses taped to his face "so he could see what he was doing."

Kentucky State Police Capt. Lisa Rudzinski said the investigation revealed that the letters "fed" scrawled on his chest in black pen had been written from the bottom up and Sparkman's DNA was the only forensic evidence found at the scene.

He was touching the ground, and to survive "all Mr. Sparkman had to do at any time was stand up," she said.

Sparkman spoke to a witness they wouldn't name about hanging himself and making it look like someone else killed him, according to Rudzinski.

Authorities say Sparkman acted alone in manipulating the scene to conceal the suicide.

"Our investigation, based on evidence and witness testimony, has concluded that Mr. Sparkman died during an intentional, self-inflicted act that was staged to appear as a homicide," Rudzinski said.

Sparkman's mother, Henrie Sparkman of Inverness, Fla., bristled at the conclusion: "I disagree!" she wrote in an e-mail to The Associated Press.

Investigators believe he killed himself and made it look like a murder because he'd recently taken out two life insurance policies that wouldn't pay out for suicide.

But they didn't say what motivated Sparkman to end his life in the first place. He didn't leave a note, Rudzinski told reporters.

If Sparkman had been killed on the job, his family also would have been be eligible for up to $10,000 in death gratuity payments from the government.

He was not eligible for a separate life insurance policy through the government because his census work was intermittent, Census Bureau spokesman Stephen Buckner has previously said.

The Census Bureau suspended door-to-door interviews in the rural county after Sparkman's body was found.

Anti-government sentiment was initially one possibility in the death. Authorities said Sparkman had discussed perceived negative views of the federal government in the area.

A friend of Sparkman's, Gilbert Acciardo, previously told The Associated Press that he warned Sparkman to be careful when he did his census work.

Acciardo, a retired Kentucky state trooper, said he told Sparkman people in the rural area would perceive him differently because he worked for the federal government.

Henrie Sparkman has said her son was an Eagle scout who moved to the area to be a local director for the Boy Scouts of America. He later became a substitute teacher in Laurel County and supplemented that income as a census worker.

Friends and co-workers have said that even while undergoing chemotherapy for cancer, Sparkman would show up for work smiling with a toboggan cap to cover his balding head. They said he was punctual and dependable.

The Associated Press contributed to this report.