Omaha, Neb. ? A Chadron State College professor whose burned body was found bound to a tree in a field may have bought the charcoal briquettes that killed him, the Dawes County Attorney said Wednesday.

But Dawes County Attorney Vance Haug stopped short of saying Steve Haataja’s death was a suicide, saying investigators haven’t ruled out homicide or an accident.

Investigators found ashes and unburned briquettes next to the mathematics professor’s body, and a grocery store clerk told investigators the professor bought a 7-pound bag of charcoal on the day investigators believe he was last seen alive, Haug said.

The clerk told investigators that Haataja was alone when he bought the briquettes, and investigators who searched his home found no briquettes or a device – such as a grill – to use them.

Haug said it was “significant” that the unburned briquettes were similar to the ones Haataja bought Dec. 4, the last night he was seen, although he would not confirm that the briquettes found near his body were the ones he bought.

“Investigators consulted with people in the charcoal industry and made some comparisons and observations about the briquettes,” Haug said. “I don’t want to get too specific because I don’t want to draw conclusions that I don’t think are appropriate.”

Haug said earlier that there’s no evidence yet that anyone was with Steven Haataja when he died.

Haataja’s wrists were not bound, and Haug has said the 46-year-old professor could have tied himself to the tree.

Haataja had likely consumed large amounts of alcohol before he died, Haug said, and an autopsy showed high levels of carbon monoxide in his system.

Forensic pathology and toxicology testing found Haataja died of smoke and soot inhalation, combined with thermal injuries, authorities said earlier.

Tim Sorenson, Haataja’s best friend, has said Haataja had a history of depression and was hospitalized because of it last year. Haug said in May that Haataja tried to commit suicide last year.

Haug has said there was no suicide note, nor any indication Haataja was thinking about suicide.

Haataja disappeared from this city of 5,600 in December. Police saw no signs that he planned to leave and have acknowledged they did little to search for the professor. In March, ranchers chasing a runaway steer found him burned to death in the hills just south of the small school where he taught.

Some people in Chadron speculated whether Haataja was the victim of a hate crime, possibly because of his sexual orientation.

But Haug has said extensive background information points to his being heterosexual.