BANGKOK (AP) — A former policeman burst into a day care center in northeastern Thailand on Thursday, killing dozens of children and teachers and then firing on more people as he fled in the deadliest rampage in the nation’s history.

The assailant, who authorities said was fired from the force earlier this year because of a drug offense, took his own life after killing his own wife and child at home.

A witness said staff at the day care locked the door when they saw the assailant approaching with a gun, but he shot his way in. In footage posted online after the attack, frantic family members could be heard weeping outside the day care, and one image showed the floor of one room smeared with blood and sleeping mats scattered about. Pictures of the alphabet and other colorful decorations adorned the walls.

At least 37 people were killed in the attack, according to police spokesman Archayon Kraithong. Another 12 people were wounded. At least 24 of the dead were children, mostly preschoolers.