CERRITOS, Calif. (KABC) -- A man was killed in a shooting on the westbound 91 Freeway near Cerritos Friday, authorities said.The incident happened shortly before 5 p.m. on the freeway, east of Artesia Boulevard.It was unclear what led to the shooting, but authorities said the 27-year-old Cerritos resident was shot once in the chest and died at an Irvine hospital.His family was notified and they are cooperating with law enforcement.Authorities are not ruling anything out but said a motive remains unclear."It could be a multitude of things - it could be road rage because we have seen that in the past. I don't know much about the victim. Thus, I can't speculate whether it was gang-related or not," CHP Sgt. Saul Gomez said.No further details of the crime, such as a suspect description, were released.All westbound lanes were blocked until about 1:30 a.m.Anyone with more information is urged to call the California Highway Patrol.