Cause of crash that killed LAPD cop unknown

DIAMOND BAR, Calif. The officer, identified as 37-year-old Jacqueline Montalvo, was heading northbound on Grand Avenue when, for unknown reasons, she swerved across the center divider and head-on into oncoming traffic at about 5:30 p.m.

She slammed into a pickup truck, which then triggered a chain-reaction accident involving two more vehicles. One of those vehicles overturned.

Montalvo was declared dead at the scene. One victim was airlifted to a local hospital in critical condition, and two other victims were hospitalized, but the extent of their injuries is unknown at this time.

The area was shutdown all night as authorities investigated.