The fatal accident occurred a little before 11 a.m. on the northbound freeway, west of El Segundo Boulevard, the California Highway Patrol reported.
It was unclear if the motorcyclist or the passenger was killed in the crash. Paramedics rushed one person to a hospital, said CHP Officer Peter Nicholson. That person’s condition was not immediately known.
A representative from the Los Angeles County coroner’s office was called to the scene a little after noon.
The accident blocked traffic on all but the two right lanes of the northbound 405 between the 105 Freeway and Century Boulevard.