According to police, the body was found near E. Ocean Boulevard and Corona Avenue after receiving a report regarding a strong odor coming from inside the vehicle.
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When officers arrived, they found the body of a man - who was identified as 41-year-old Deondre Washington - on the seat.
The Los Angeles County medical examiner later determined he had multiple gunshot wounds on his upper body.
Detectives are working to determine the motive behind the shooting, but information regarding a suspect or suspects is unknown.
Anyone with information is urged to call Det. Sean Magee or Juan Carlos Reyes at 562-570-7244. People can also submit anonymous tips by calling L.A. Crime Stoppers at 800-222-TIPS (8477) or visiting www.lacrimestoppers.org.