SILVER SPRING, Md. — The shooting spree began with a domestic slaying in an unusually public place. According to police, Eulalio Tordil, a federal security officer, shot and killed his estranged wife as she waited to pick up her children in the parking lot of a suburban Washington high school on Thursday afternoon. He also shot and wounded a bystander who tried to intervene, police said.

Detectives worked through the night but weren’t able to catch him. The next day he struck again, this time apparently choosing his victims at random.

On Friday Tordil shot three people outside an upscale mall in Bethesda, 15 miles away. One man died and two others were wounded, one of them critically. Then, he drove to a supermarket five miles away in Silver Spring, where he fatally shot a woman who was sitting in her car, police said.