A gunman opened fire yesterday in the crowded Clackamas Town Center mall in suburban Portland, Ore., killed two people and seriously injuring a third before killing himself, according to a report from Good Morning America.

The shooter has been “tentatively” identified by police, though they have not yet released his name. Police have also not released the names of the deceased.

The shooter, wearing a white hockey mask, black clothing and a bulletproof vest, entered the mall around 3:30 p.m. Tuesday, moving through a Macy’s store and proceeding to the food court and public areas firing the gun – what witnesses believed to be a black, semi-automatic rifle, the article says.

More than 10,000 shoppers were at the mall that day, according to police. Clackamas County Sheriff Craig Roberts says that more than 100 law enforcement officers responded to the shooting, and four SWAT teams swept the 1.4 million-square-foot building searching for the shooter. He was eventually found dead of an apparent suicide, the article says.

Roberts also noted that three shoppers – two emergency room nurses and one physician – provided medical assistance to victims who had been shot. Other shoppers helped escort individuals out of the mall.