PORTLAND — The Maine supreme court has upheld murder convictions for a 23-year-old man whose lawyer said he was “played” by a skilled law enforcement officer during an interrogation.

The defense contended Thayne Ormsby’s remark that “I’m going to have to plead the fifth on that one” should have been enough for the detective to end the interrogation.

But the Maine Supreme Judicial Court ruled unanimously on Tuesday that Ormsby’s confessions were made voluntarily and that their admission during his trial didn’t violate his Fifth Amendment rights.

The court also upheld his sentence of three life terms.

Ormsby was convicted last year of three counts of murder and one count of arson for the 2010 stabbing deaths of Jeffrey Ryan, his 10-year-old son and a family friend in the town of Amity.