Story highlights Ramarley Graham was fatally shot in 2012

Federal prosecutors closed their investigation last year, citing insufficient evidence

(CNN) A New York police officer who fatally shot unarmed teen Ramarley Graham during a 2012 chase, resigned Sunday after an internal disciplinary trial on Friday.

According to an NYPD statement, police officer Richard Haste quit after the NYPD trial commissioner "found him guilty on all counts and recommended his employment be terminated."

NYPD Police Commissioner James O'Neill has "fully concurred with the findings and recommendations of the Trial Commissioner," the statement reads.

In 2013, Haste pleaded not guilty to charges of first- and second-degree manslaughter for the February 2, 2012 shooting of 18-year-old Graham. A Bronx Supreme Court Judge later dismissed the manslaughter indictment against Haste. The judge had thrown out the case based on instructions given by the prosecution to the grand jury regarding communications among officers before the shooting.

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