DOVER-FOXCROFT – A Maine State Police trooper who shot and killed a gunman during a standoff initially was unaware that the man was communicating with law enforcement on a different radio channel and fired the fatal shot when the county sheriff walked toward the man, the Attorney General’s Office said Monday.

Trooper Jon Brown fired three shots at Michael Curtis without realizing that Curtis, a firefighter, was speaking with the sheriff on a channel used by the fire department, according to a report by the Attorney General’s Office.

Attorney General William Schneider concluded that the trooper met the legal requirement for using deadly force because he thought the sheriff faced an imminent threat.

Curtis, who had been drinking, had ignored orders to drop the .40-caliber semiautomatic handgun that he had used earlier to kill his wife’s ex-husband at work at the Hilltop Manor nursing home on Nov. 29.

The standoff happened at a fairground, where Curtis, 46, began communicating with law enforcement officials on a two-way radio on a channel used by fire officials.

Sheriff John Goggin offered assurances, unbeknownst to Brown, that Curtis would not be harmed. But Brown shouted for the gunman to “show your hands!” and fired the initial volley.

That prompted Curtis to exclaim, “I want help, but nobody seems to want to help me, all they want to do is shoot me,” the report said.

Afterward, Goggin walked toward Curtis, despite concerns voiced by several officers. Brown yelled several warnings for the sheriff to “get out of the field” before firing the fatal shot, the report said.