A man was shot and killed by police Monday after he ignored pepper spray and officers' commands and attacked a state trooper with a chain saw, authorities said.

At least 13 bullets struck William Henkle after state and local officers who had surrounded him opened fire, police said.

Henkle, 40, allegedly struck Trooper Michael Hartzel in the shoulder, lower back and buttocks with the saw. The trooper was treated for minor injuries at a hospital and released.

Henkle called 911 early Monday and said he was having a heart attack, but when police and an ambulance arrived, he was outside the house with the chain saw running, said Capt. Kenneth Hill, commander of the state police barracks at Wyoming.

About 10 state and local officers formed a semicircle around Henkle and ordered him to drop the chain saw, but he revved the saw and refused to put it down, Hill said.

Police said they used pepper spray, then fired when Henkle lunged at Hartzel.