LAPD has released video in the fatal shooting of an unarmed 18-year-old by a plainclothes officer

Ricardo Ramirez Jr., 18, of Richmond, Calif. was fatally shot on the night of July 13 by a vice sergeant.

His family is planning to sue the department, saying the teen was unarmed and did not even know he was approaching an armed police officer that evening.

LAPD says the teen was wearing a ski mask and was shot after the car he was in pulled over and blocked off lanes and two occupants got out and approached the other vehicle.

The sergeant who shot the teen was not wearing a body camera, but the new footage includes surveillance video from nearby cameras as well as bodycam footage from officers who responded afterward.

The incident started as LAPD officers were conducting a prostitution enforcement operation in the Figueroa Corridor. They saw a silver Cadillac pull up in front of a Toyota Camry, and the masked occupants get into a heated exchange with those in the other vehicle.

The Toyota took off.

As the Cadillac also left the scene, a vice sergeant in an unmarked vehicle followed.

An officer's voice on radio traffic can be heard stating: "Follow that car because they were all masked up. Follow that car."

The Cadillac soon pulled over in a residential neighborhood near 66th and Flower streets in South Los Angeles. It turned around and partially blocked the roadway, and the occupants got out.

One occupant approached the passenger side, while another - later identified as Ramirez and described as wearing a mask - approached the driver's side of the unmarked police vehicle. Ramirez can be seen immediately falling to the ground as he was shot once in the chest from the police vehicle.

The second man returned to the Cadillac, which fled from the scene. Other officers arrived at the scene, and they attempted to render medical aid to Ramirez until paramedics arrived. He was brought to a nearby hospital and pronounced dead there.

Other LAPD officers and the CHP engaged in a lengthy chase of the Cadillac, which eventually ended in a surrender on the northbound 15 near the 138 in San Bernardino County. The driver, Israel Dezama, 26, of Pittsburg, Calif. was arrested for felony evading. The other two occupants were questioned and released.

No weapons were recovered from the Cadillac or Ramirez.