18-year old Ramarley Graham was killed when a police officer entered Graham's grandmother's apartment.
Now Graham's family is accusing the NYPD of improperly training officers and unfairly targeting minorities.
They also say the NYPD tried to cover up Graham's death.
Officer Richard Haste has pleaded not guilty to manslaughter charges in the teenager's death.
The shooting stemmed from an NYPD investigation of a persistent drug trade in the Bronx neighborhood where Graham lived.
At the time, police said an observation team identified Graham as a potential suspect and radioed to other officers that he appeared to be armed with a pistol.
A civilian witness told police that around the same time, two police officers in plain clothes but wearing NYPD raid jackets pulled up and yelled at a man - apparently Graham - "Police! Don't move!"
After the man ducked into Graham's three-family home, the officers found a back entrance, climbed some stairs and broke down the door to a second-floor apartment where Graham lived with his grandmother and other family, police said.
An officer positioned behind the shooter reported seeing Graham run toward a bathroom, possibly to flush away some marijuana. He also heard Haste yell, "Show me your hands!" and "Gun! Gun!" before a shot rang out, police said.
Haste fired one shot at close range from his 9mm semiautomatic handgun, police said. The victim was struck in the upper chest and collapsed inside the bathroom, as his grandmother and 6-year-old brother stood nearby. He was pronounced dead at a hospital.
A search of the apartment failed to turn up any weapons.
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