The person suspected of vandalizing the Dorchester Vietnam Memorial Thursday is in custody. Volunteers cleaned up the mess that was made — crude writings on stones, upturned foliage and small American flags tossed into a nearby creek — in time for Memorial Day.

The 33-year-old man believed to be the culprit was apprehended Saturday morning by law enforcement. His name hasn't been released, but State Police say he is undergoing mental health evaluation and treatment at a Boston hospital, according to a statement.

When Joe Zinck, the president of the Dorchester Vietnam Committee, first heard about the vandalism, he said he was shocked.

"Why would anyone do that to the Vietnam memorial?" Zinck first thought. A Vietnam veteran himself, Zinck said he knew most of the men whose names are on the monument.

"We're — [everybody] in the area — hurt that somebody would would have no respect for the memorial itself," he said.

This memorial was also vandalized last October.

Zinck said he's glad the suspect is in custody and he's happy volunteers helped restore the monument in time for a Memorial Day ceremony.

"I will sleep a little better tonight, knowing the person who damaged the memorial won't be around to do it again over the weekend," Zinck said.