Police say the 24-year-old man who killed two teenage girls and wounded seven other people as he fired shots at them on a Portland, Ore., sidewalk has died.

Police say Erik S. Ayala shot himself in the head after the Saturday rampage, and he died Tuesday at a hospital.

Investigators say they don't yet know what sparked Ayala's actions.

A local teenager and an exchange student from Peru died. Several of the wounded also were exchange students. The group was outside an under-21 nightclub where they had been celebrating a birthday.