Seattle police are still investigating the few details that remain unknown after the shooting rampage by Ian Stawicki on Wednesday that left five people dead and ended with his suicide.

Stawicki shot five people at Cafe Racer in the University District, four fatally, before making his way to downtown Seattle, where he shot a woman and took off in her vehicle.

How he got there from the University District is not clear.

According to Assistant Police Chief Jim Pugel, detectives are examining three primary possibilities: Stawicki may have used his mother's truck, gotten a ride from someone or hopped on a bus.

However, police have been unable to locate the family's truck anywhere near the second shooting site, he said. No one claims to have given Stawicki a ride, although one woman came forward and told police he attempted to flag her down near the Cafe Racer shooting scene, but she declined to stop, he said.

Police have not yet been able to find surveillance videos from Metro Transit buses that would confirm whether Stawicki may have gotten on a bus, he said.

Police spokesman Mark Jamieson said on Friday, "You do realize we may never know that, right?"

Stawicki shot himself about five hours after the coffee-shop shootings as police surrounded him in a West Seattle neighborhood.