DOVER-FOXCROFT — State police investigators have not pinpointed why a sheriff’s department dispatcher gunned down his wife’s ex-husband before being he was fatally shot by a trooper, officials said today.

No single issue emerged today to suggest what sparked the violence, said Stephen McCausland, spokesman for the Maine Department of Public Safety.

“Trying to explain an inexplicable act isn’t always easy,” McCausland said.

Piscataquis County sheriff’s dispatcher Michael Curtis, 46, went to the Hilltop Manor nursing home in Dover-Foxcroft just before 9:30 a.m. Tuesday and shot Udo Schneider, officials said. Afterward, Curtis drove his pickup truck to a fairground, where he was shot by a trooper after a standoff with officers.

An autopsy today determined that Curtis died from a single gunshot wound. Schneider’s autopsy won’t be completed until Thursday.

Maine State Police detectives are investigating Schneider’s killing and the Attorney General’s Office is investigating the shooting of Curtis. The trooper who shot Curtis is on paid leave pending the outcome of the investigation.

After the shooting, the ground outside the nursing home was littered with shell casings. Police didn’t say whether the semiautomatic handgun he used was issued by the sheriff’s department.

The shootings left both communities unsettled, and acquaintances of Curtis were at a loss to explain his violent outburst.

In addition to being a dispatcher, Curtis was a lieutenant in the fire department in Sangerville, where both men lived. He also was a former deputy fire chief in Dover-Foxcroft.

Dover-Foxcroft Fire Capt. Eric Berce told the Bangor Daily News that he’d known Curtis for a quarter-century and that they were close friends. He said the lack of answers and rumors floating around town were frustrating. “He was not a monster,” Berce said.

Schneider was well-liked. He was director of maintenance at two of the 11 long-term care facilities operated by Rockland-based Davis Long Term Care Group Inc., and the company’s CEO described him as a “wonderful man.”