The mother of an unarmed teenager killed by an NYPD cop in 2012 during a narcotics investigation questioned Thursday why the de Blasio administration is still keeping all records about the case secret.

Constance Malcolm, whose son Ramarley Graham was shot dead in their Bronx home, said her latest disappointment in the city’s treatment of her family came Jan. 31.

That’s when the NYPD denied her attorney’s months-old request for the department’s records on the shooting under state Freedom of Information law.

“It’s very frustrating not knowing what happened to my son,” she said at a news conference outside City Hall. “I’ve been fighting for five years — five years!”

Graham, 18, was shot to death by Officer Richard Haste on Feb. 2, 2012. During testimony at his departmental trial, Haste said he thought Graham, the object of a police drug surveillance operation, had a gun and was about to use it when the officer opened fire.

Officers later found marijuana, but no gun, in the bathroom toilet.

A state grand jury had initially indicted Haste, but the case was dismissed because of a prosecutorial mistake. A second panel did not indict him. The city paid the family $3.9 million to settle a civil case.

Haste’s internal disciplinary trial wrapped up earlier this year. The NYPD reversed its prior stance — that the results of the trial would be kept secret — and said the family would learn what the department decides. Pending the outcome, Haste remains on the force, without his gun and badge, on desk duty.

“You will look at every case of police misconduct or police murder and you will see that a blue wall of silence goes up, so today is no different. The blue wall is up. It has been up for five years," Councilwoman Rosie Mendez (D-Manhattan) said at the news conference.

Graham’s lawyer, Gideon Oliver, showed letters indicating that the open-records request was denied on the claim that disclosure would interfere with a law enforcement investigation or judicial proceeding. He questioned the merits of the claim, noting that authorities have ruled out criminal charges against Haste.

De Blasio spokesman Austin Finan referred a request to comment to the NYPD, which did not return a message seeking that comment.