The attorney for the family of Reynaldo Cuevas is filing a notice of claim Monday against the city and the officer who fired the shot.
Cuevas, a convenience store worker, was shot and killed last September while fleeing an armed robbery in the Bronx.
The NYPD called it a traffic accident.
Attorney Sanford Rubenstein said the wrongful death lawsuit would hold the officer and the city "civilly accountable for the wrongful death."
Cuevas plowed into the officer while fleeing, sending both men tumbling to the sidewalk.
Police said investigators believed the impact of Cuevas running into the officer caused him to fire one round, striking the 20-year-old victim.
Rubenstein says he plans to file a $25 Million claim against the city on Monday for the shooting of Cuevas by Officer Remysh Bangali in September outside a Bronx bodega.
"District Attorneys need the police, they need detectives to make their cases against ordinary criminals," said Rubenstein, "they should not be charged with the responsibility of prosecuting the police when they commit a wrongful act."
The NYPD says surveillance video shows the shooting was accidental. They say Cuevas ran out of the bodega during a robbery, and right into officer Bangali, who was responding with his weapon drawn.
The gun discharged as the two fell to the sidewalk and Cuevas was killed.
Clutching a picture of her son, Ana Milagros Cuevas said she wants Officer Bangali to be fired.
The NYPD will conduct its own review to see if Officer Bangali violated department rules.
A spokesman for the Bronx DA has been quoted as saying a review of the evidence has shown the officer did not commit a crime.