The death is fuelling speculation he was killed simply because he worked for the federal government – now the target of a wave of hate from extreme right-wingers.

Colleagues of Bill Sparkman, a 51-year-old single father and census volunteer, alerted police after the normally dependable part-time teacher failed to turn up for work on September 10. His corpse was discovered two days later, near a cemetery in the Daniel Boone National Forest. Preliminary medical reports indicated he had been asphyxiated.

Sparkman had been warned the people of rural Clay County do not always welcome federal visitors on official business. Gilbert Accairdo, who worked with him at Johnson Elementary School, said he was aware of the potential risks.

“As a retired state trooper, I recognised the inherent dangers of going to someone’s house and [them] not knowing what you’re about,” he said. “The thing I stressed with Sparkman was to make sure people know you are just there to gather statistics.

“The area he went into is isolated, with no phone service, so I said: ‘Hey, be careful when you’re over that way’. He was so naive, though, always looking for the good in people. There is a lot of bad in the world and he did not see it.”

Dave Breyer, of the regional FBI field office in Louisville, sought to play down assumptions a violent dislike of bureaucratic interference could have motivated the killer.

“I think to give this impression he was strung up because he was a federal employee is giving a bad impression to the nation,” he said. Even so, it is highly unusual for the bureau still to be investigating a routine homicide two weeks after the event.

The gruesome find has triggered national interest because it comes at a politically sensitive time, not long after thousands of angry conservatives marched on Washington to protest at government intervention in the economy, public healthcare and the prospect of higher taxes.

“Take our country back,” was a common refrain. One sign read “next time we’re bringing our guns, and that will be your fault”. The most popular shows on the right-wing Fox News channel routinely denounce Barack Obama’s administration as socialist, fascist, or both.

Dee Davis, president of the Centre For Rural Strategies, in Whitesburg, not far from the crime scene, said people in south-eastern Kentucky are independent, but hardly anarchists.

“It’s not like people round here have Rush Limbaugh neck tattoos,” he said (Limbaugh is a radio show host and conservative political commentator). “There has been a quick assumption people here hate their government. If you look at the rates of military service, the number of people who have served and died in the Middle East, it shows that is not true.”

The area is desperately poor. “Clay County is one of four eastern Kentucky counties with an average income less than that of Kazakhstan, Uruguay or Cuba,” said Davis. “The life expectancy is less than Mexico or China.”

An economy in transition, following the loss of thousands of coal mining jobs, cannot compete with the black market in illegal drugs. Carl Greene, a reporter at local newspaper the Times-Tribune, said it was just as likely Sparkman stumbled upon a drug operation. “The mountain people grow a lot of marijuana,” he said. “There are methamphetamine labs there. The place has gotten

a reputation. It is an area where the law is sometimes ignored.”

In the prohibition era of the 1920s and 30s – when selling, manufacturing, and transporting alcohol for consumption was banned nationally – the nearest federal courthouse was famous for trying more moonshine cases than any other in the land.

For the time being, all census collection in the area has been suspended. The FBI, working in tandem with Kentucky state police, is refusing to rule anything out, including the possibility Sparkman was unlucky enough to meet someone just as their anger at the Washington establishment boiled over.

John Berry, who runs the Office of Personnel Management in charge of the survey, said he was confident Sparkman’s killer would be brought to justice. “If this is an assault on a federal employee the full force and weight of the federal government will come down on these perpetrators as hell hath no fury,” he said. “By God, it will not be tolerated.”