WARREN – A Maine State Prison corrections officer was taken to Penobscot Bay Medical Center in Rockport late Monday after being hit on the head with a rock allegedly thrown by a prisoner.

On Wednesday, Warden Jeffrey Merrill said the incident occurred late in the day Monday and was still under investigation.

The officer received “liquid stitches” at the hospital, he said, then was released. The prison went through a so-called shakedown Tuesday, he said, and a suspect has been identified.

“We will hold that person accountable,” Merrill said, noting he is working with the District Attorney’s Office on bringing charges.