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

No single issue emerged Wednesday 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 Wednesday determined that Curtis died from a single gunshot wound. Schneider’s autopsy won’t be completed until today.

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 semi-automatic 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.