Update 12/1 (a fourth person has now died from their gunshot wounds)

OXFORD TOWNSHIP, Mich. (AP) — A 15-year-old sophomore opened fire at his Michigan high school on Tuesday, killing three students and wounding six other people, including a teacher, authorities said. Oakland County Undersheriff Mike McCabe said at a news conference that he didn’t know what the assailant’s motives were for the attack at Oxford High School in Oxford Township, a community of about 22,000 people roughly 30 miles (48 kilometers) north of Detroit.

Officers responded at around 12:55 p.m. to a flood of 911 calls about an active shooter at the school, McCabe said. Authorities arrested the suspect at the school and recovered a semi-automatic handgun and several clips. “Deputies confronted him, he had the weapon on him, they took him into custody,” McCabe said, adding that suspect wasn’t hurt when he was taken into custody and he refused to say how he got the gun into the school. Authorities didn’t immediately release the names of the suspect or victims.