Bill Sparkman had taken out insurance policies shortly before his death

A US census worker who was found hanging naked from a tree and bound with duct tape killed himself but made it look like a murder, authorities say.

Bill Sparkman, 51, was found dead on 12 September in rural Kentucky with the word "Fed" scrawled on his chest.

Authorities investigated the mysterious death to see whether Sparkman was the victim of anti-government sentiment.

Investigators concluded the word "Fed" had been written from top to bottom and Sparkman alone manipulated 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," said Kentucky State police captain Lisa Rudzinski.

"A thorough examination of evidence from the scene, to include DNA testing, as well as examination of his vehicle and his residence resulted in the determination that Mr Sparkman, alone, handled the key pieces of evidence with no indications of any other persons involved."

It was also discovered that Sparkman had recently taken out prior to his death two accidental life insurance policies totalling $600,000 (£362,000), and that if he was killed on the job his family would receive an additional $10,000 from the government.

However, the life insurance policies did not cover suicide.