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The New York Police Department announced on Monday that it will allow disciplinary proceedings to go forward against a patrolman accused in the notorious chokehold death of an unarmed black man, saying it's run out of patience with federal authorities' indecision about whether to bring a criminal case.

On the eve of the four-year anniversary of Eric Garner's killing, a pointed letter from the NYPD's top lawyer informed the U.S. Department of Justice of an administrative case that could result in dismissal for the white officer, Daniel Pantaleo, because "there is no end in sight" to the federal probe.

Typically, the department waits for federal prosecutors to conclude civil rights violations inquiries before taking action. But other probes have taken far less time than the case of a victim whose dying words, "I can't breathe," became a slogan for the Black Lives Matter movement.

"Based on our most recent conversations, it has become clear that a definite date by which time a final decision by the U.S. DOJ will be rendered in this matter cannot be predicted," Lawrence Byrne, deputy commissioner for legal matters, wrote to prosecutor Paige Fitzgerald.

"The NYPD has come to the conclusion that given the extraordinary passage of time since the incident without a final decision on the U.S. DOJ's criminal investigation, any further delay in moving ahead with our own disciplinary proceedings can no longer be justified," Byrne added.

A police watchdog agency, the Civilian Complaint Review Board, will prosecute Panteleo under a memorandum of understanding with the NYPD, according to Byrne.

In a statement, the DOJ said it already told the Police Department in the spring it could go forward and that the move "does not have any bearing on the decision-making timeline."

A lawyer for Pantaleo, who's been on paid desk duty, declined comment on Monday. Pat Lynch, head of the Patrolmen's Benevolent Association, called on DOJ to close its case but said that the officer deserves due process in the disciplinary process.

There was no immediate comment from an attorney for Garner's family, which received $5.9 million from the city in 2015 to settle a wrongful death claim.

"We want to see this done. ... We want justice," Garner's mother, Gwen Carr, said at a press conference Monday with the Rev. Al Sharpton, who praised the move but also called on the U.S. attorney general to move forward with federal action.

The family and police reform activists have expressed deep frustration over the inaction by federal authorities and the NYPD after a state probe ended without criminal charges.

The 43-year-old Garner, who was accused of selling loose, untaxed cigarettes, was stopped by police on Staten Island on July 17, 2014, and refused to be handcuffed. Pantaleo is seen on a widely watched cell phone video putting Garner in an apparent chokehold, which is banned under NYPD policy.

The heavyset victim, who had asthma, is heard gasping, "I can't breathe." He was pronounced dead at a hospital. The medical examiner ruled the death a homicide caused in part by the chokehold.

Garner's death sparked angry protests about the treatment of black men and boys at the hands of white police officers.