MACHIAS, Maine — Sgt. Troy Lyons, a Washington County corrections officer, was assaulted by an unknown assailant Monday night as he was conducting a routine perimeter check outside the county jail.

Lyons sustained lacerations to his forehead and a bruised shoulder when the assault occurred at approximately 10:30 p.m. He was treated for his injuries at Down East Community Hospital in Machias and released.

“We have nothing,” Sheriff Donnie Smith said Tuesday, referring to motive or suspects. “It happened back by the garage area, where it’s dark and there are no cameras. We’ve looked at all the video, and there’s nothing to go on there.”

Smith said no words were exchanged between Lyons and his assailant.

“Troy said he heard a noise and at first thought it was the wind.”

Smith said Lyons is temporarily off duty as a result of his injuries.