The Brooklyn district attorney will not appeal Peter Liang’s reduced conviction in the November 2014 fatal shooting of an unarmed man — a decision that comes a little more than a month after NBC News first learned that the former rookie cop would also not appeal.

Former police officer Peter Liang sits in court for sentencing in New York, Tuesday, April 19, 2016. Liang, convicted in the accidental shooting death of an unarmed man, Akai Gurley, in a darkened stairwell was spared prison time Tuesday, and a judge reduced his manslaughter conviction to a lesser charge. Jesse Ward / AP

The DA’s office notified the New York State Supreme Court appellate division in a letter dated Dec. 6. Enclosed were documents, dated four days earlier, that agreed to the terms.

They were signed by Liang, his appeals attorney, and a representative for Acting District Attorney Eric Gonzalez, court records show.

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“The decision by both sides to withdraw their appeals means that Mr. Liang has waived any and all rights to challenge his conviction in state or federal court,” a spokesperson for the Brooklyn DA’s office told NBC News in an email. “Given the unlikelihood that we would prevail on our appeal, this agreement is the best way to protect the integrity of the conviction and marks the end of a successful prosecution."

“Given the unlikelihood that we would prevail on our appeal, this agreement is the best way to protect the integrity of the conviction and marks the end of a successful prosecution."

Liang and his partner Shaun Landau were patrolling a darkened stairwell at the Louis H. Pink Houses in Brooklyn when Liang, who had his gun drawn, was startled and accidentally fired a shot. The bullet bounced off a wall and struck 28-year-old Akai Gurley, who had entered with friend Melissa Butler from a floor below.

Following a 911 operator's instructions, Butler performed CPR on Gurley, who had collapsed in the stairwell and later died. At his trial, Liang testified that he didn't administer the life-saving procedure because he felt he wasn't adequately trained in it.

Liang was convicted in February of second-degree manslaughter and faced up to 15 years in prison. Following the verdict, the New York Police Department (NYPD) fired both officers.

At Liang’s sentencing, Justice Danny Chun reduced the charge to criminally negligent homicide and spared him jail time. Liang was instead given five years probation and required to complete 800 hours of community service, which he finished a week before Thanksgiving, according to Karlin Chan, a close supporter who told NBC News last month about Liang’s decision not to appeal.

Akai Gurley's daughter Akaila reacts on her mother Kimberly Ballinger's lap as reverend Al Sharpton speaks at the National Action Network in the Harlem borough of New York November 22, 2014. CARLO ALLEGRI / Reuters

This past summer, the city settled a wrongful death lawsuit with Kimberly Ballinger, Gurley’s domestic partner and mother of his daughter. She'll receive more than $4 million, with Liang paying $25,000.

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Last month, a judge dismissed a separate lawsuit filed by Butler, Gurley’s friend who performed CPR on him the night he was killed. Butler sought money and damages for the emotional distress she said she suffered stemming from the night of the shooting.

New York State law, however, allows only direct family members to recover damages for emotional injuries, her attorney had told the New York Daily News.

Melissa Butler, Akai Gurley's girlfriend, reads a statement in court during the sentencing of former police officer Peter Liang in New York, Tuesday, April 19, 2016. Liang, convicted in the accidental shooting death of an unarmed man, Akai Gurley, in a darkened stairwell was spared prison time Tuesday, and a judge reduced his manslaughter conviction to a lesser charge. Jesse Ward / AP

That was the last suit filed against Liang, who is now looking for a job, according to Chan.

“He will not be appealing the conviction and hopes to put this behind him and spare Mr. Gurley’s family any further stress,” Chan told NBC News. “This in effect closes this case, and hopefully we can all begin to heal and unite as communities of color.”

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