The police vehicle was parked at 183rd Street and Morris Avenue in the Tremont section of the Bronx.
Officer Miosotis Familia, who worked out of the nearby 46th Precinct, was sitting inside writing in her memo book.
The video shows the suspect -- who police identified as 34-year-old Alexander Bonds -- walk up to the side of the vehicle, near the side door that he would fire a bullet through.
WATCH THE SURVEILLANCE VIDEO:
After she was shot, the video then shows a flood of officers moving into the neighborhood to help the fallen officer. At the same time, Officer Familia's partner radioed for help.
Next, an ambulance arrives, eventually taking the injured officer to St. Barnabas Hospital, where she died a short time later.
Meanwhile, other officers ran outside and spotted the suspected gunman running about a block away.
Bonds drew a revolver and the officers fatally shot him, police said.
STACEY SAGER HAS MORE ON THE SUSPECT
BEFORE THE SHOOTING
Bonds had returned home from his fast food restaurant job around 7:30 p.m. on July 4. Neighbors told police he was drinking with them at the corner.
At around 9 p.m., Bonds' girlfriend called 911, reporting he had wandered off. She said he seemed paranoid and was generally acting strangely.
She said she was concerned about Bonds and asked police to find him and check his welfare.
Asked by the operator if he was armed or violent, the girlfriend said no.
She gave them one street corner to look, and then another during a second call.
Police and an ambulance crew responded to the locations, but Bonds could not be found. The incident was classified as an "emotionally disturbed person" call and closed out.
Police are investigating what may have prompted Wednesday's shooting, which Police Commissioner James O'Neill described as an officer being "assassinated in an unprovoked attack on cops."
"Officer Familia was murdered for her uniform and for the responsibility she embraced," O'Neill said in a message to officers Wednesday night. "For the NYPD, regularly achieving lower and lower crime figures means absolutely nothing when one of our own is brutally shot and killed."
Familia worked her entire police career in the Bronx precinct where she was killed while staffing the RV-like command post, stationed to help combat rising crime in the neighborhood after a triple shooting in March.