A suspect is in custody after a mass shooting in an Idaho shopping center on Monday in which at least two victims were killed and four others wounded, including a police officer, Boise Police Chief Ryan Lee said. Two more people, he said at a news conference, were in the midst of “processing, to make sure they are not injured.” Lee said he could not “stress how traumatic this is” for the community, the victims, and their families, whom the department was still working to notify at the time of the conference.

Officers responded to reports of shots fired at the Boise Towne Square Mall, the city’s largest shopping center, at around 1:50 p.m. Monday. There was “an exchange of gunfire,” Lee said, during which the officer was hit. A single suspect was taken into custody shortly afterward. The chief declined to speculate on any motive for the incident, saying it was “entirely too premature.” The police department is leading an ongoing investigation into the civilian aspect of the shooting, while Ada County’s Critical Incident Task Force has been activated and is heading up the officer injury inquiry.

During the conference, the city’s mayor, Lauren McLean, thanked the mall’s shopkeepers, the police, and first responders on the scene. “People still in the mall are safe,” she said. “People in Boise are safe. Your safety is our priority.” Idaho Governor Brad Little said in a statement that the victims of the “unthinkable” shooting were in his prayers.