The U.S. Justice Department announced Tuesday that it will not pursue federal ciminal civil rights charges against the NYPD officer who fatally shot an unarmed 18-year-old in the teenager's Bronx home.

Preet Bharara, the Manhattan U.S. attorney, said there was insufficient evidence against Officer Richard Haste in the death of Ramarley Graham, closing the two-and-a-half-year federal investigation.

Graham was killed by Haste inside his family's bathroom following an encounter with NYPD officers from the Street Narcotics Unit on Feb. 2, 2012.

The officers said they thought Graham had a gun on White Plains Road, and they pursued him to his 229th Street house, where Haste was captured on surveillance video kicking the door.

Haste's lawyers have said that the officer had the right to enter because people inside could have been in danger.

The officer confronted the teen inside the home, where he said he saw Graham make a motion as if he were pulling something out of his pants. The officer fired one shot, killing the teenager. Some marijuana was found, but not a gun.

A Bronx grand jury voted to indict Haste on state criminal charges, but the indictment was thrown out because of a prosecutorial mistake. Graham's family and advocates were hoping for federal civil rights charges after a second Bronx grand jury declined to indict the officer.

Haste is white and Graham was black.

But the U.S. attorney's office, an arm of the Justice Department, said it could "not conclude or prove beyond a reasonable doubt that there was a federal criminal civil rights violation."

"The weight of the evidence indicates that, at the time the shooting took place, Officer Haste believed Mr. Graham to be in possession of a firearm that was tucked into the waistband of his pants, for which Officer Haste believed Mr. Graham was reaching," the office said in announcing its decision Tuesday.

"Although Officer Haste ultimately was proven to be mistaken in his belief, the determination as to the willfulness of his actions must be assessed in light of his knowledge at the time of the shooting....The investigation revealed no evidence to refute Officer Haste’s claim that he shot Mr. Graham in response to his mistaken belief that Mr. Graham was reaching for a gun."

Bharara met with Graham's family and their representatives to inform them of this decision Tuesday. "Mr. Bharara expressed his deep sympathy to the family of Mr. Graham for their tragic loss," the office said in its statement.

Graham's family is demanding that Haste be fired immediately, along with the officers who were on the scene as well.

"Another slap in the face. My son committed no crime," said Constante Malcolm, Ramarley Graham's mother.

"Same as usual: black lives don't matter," said Franclot Graham, Ramarley's father. "To the people who we choose to say what's wrong and what's right, Ramarley's life will always matter to us."

"Police officers always get the benefit of the doubt, and the benefit of the doubt always works to our disadvantage. And that can no longer exist," said Royce Russell, the family's attorney.

The officer has been on desk duty since the killing. An NYPD Internal Affairs investigation has been ongoing since Graham's death.

"My client Richard Haste is gratified that he will not face a civil rights prosecution by the Southern District," said Stuart London, Haste's attorney. "There are no winners when there is a loss of life.

"My client now looks forward to resolving the police department's internal investigation with respect to this case," London continued.

Graham's death has been cited during numerous demonstrations after grand juries declined to indict police officers in the deaths of Eric Garner on Staten Island and Michael Brown in Ferguson, Mo. The deaths fueled a national conversation about policing and race.