Authorities on Sunday were still working to determine what prompted a 20-year-old man to open fire in a Washington state mall, killing five people. Police arrested the suspected gunman, Arcan Cetin of Oak Harbor, Washington, on Saturday. Police said he was taken into custody without incident in Oak Harbor, some 30 miles (48 km) southwest of Burlington where the shooting occurred on Friday night. Cetin opened fire at the Cascade Mall around 7 p.m.