Constantine Boyko, a 25-year-old San Francisco resident, was killed on Saturday after his motorcycle collided into a van on Cesar Chavez Street between Evans Avenue and Pennsylvania. "According to investigators, Boyko was traveling east on Cesar Chavez when he collided with the van head-on, which was traveling in the opposite direction," notes SF Appeal.

Boyko died at the scene. And the driver of the van stopped and cooperated with police. Very sad.