The mother of the paparazzo who was struck and killed by a car back in January -- after chasing Justin Bieber's Ferrari -- is suing the California Highway Patrol, claiming it's the cops' fault her son is dead.
Vickie Guerra -- mother of 29-year-old photog Chris Guerra -- claims in her suit a CHP officer abused his authority by ordering Chris to unsafely cross a busy street.
TMZ broke the story ... Chris had been photographing Bieber's white Ferrari while CHP deputies were writing the driver -- Lil Twist -- a ticket for speeding on the 405 Freeway.
In her lawsuit, Vickie claims the CHP officer noticed her son snapping photos and in a threatening manner, gesturing with his gun, the cop ordered Chris to keep his distance by crossing the street.
Vickie says her son obliged and was struck by a car traveling in excess of 40-50mph. Vickie says her son flew over the first car and was immediately run-over by a second car.
Vickie is suing the CHP and the State of California for unspecified damages. She's also suing the driver of the car that hit Chris.
Reps for the CHP had no comment.