Sign up for our COVID-19 newsletter to stay up-to-date on the latest coronavirus news throughout New York City

The district attorney let the garbage-truck driver who hit and killed a 27-year-old cyclist in Greenpoint last July off the hook because investigators’ nearly six-month probe lacked enough evidence to arrest him, a spokesman for the top prosecutor said.

Eric Gonzalez decided on Jan. 9 not to press charges against the motorist because prosecutors failed to find necessary evidence while re-examining the case after police announced they would not charge the man in August.

“Following an exhaustive reinvestigation that included interviews with all of the witnesses, a review of surveillance footage, and a consultation with an accident-reconstruction expert, we determined that we could not sustain criminal charges,” said Oren Yaniv. “We conveyed these findings to the victim’s family and expressed our deepest sympathies for their loss.”

The Police Department’s citywide accident-investigation squad started looking into the July 22 collision after the driver — an employee for private trash collector Action Carting — struck Neftaly Ramirez near Noble and Franklin streets as he pedaled home from work after midnight, and drove off without stopping.

Cops said they couldn’t arrest the motorist about three weeks after their investigation began, claiming he didn’t know he hit Ramirez following interviews with him and a colleague allegedly in the passenger’s seat at the time of the collision. And officials never released the driver’s name, claiming persons-of-interest are never identified ahead of arrests.

But the Police Department kept saying the probe was ongoing even after deciding not to cuff the driver and handing its findings over to the district attorney’s office, preventing journalists and the public from accessing the crash-investigation report. And authorities continually refused to explain what other avenues investigators and prosecutors were still exploring.

Locals slammed police in September for not arresting anyone in the wake of the fatal accident, questioning their motives for keeping the case open — a move legal experts described as a way to keep potentially incriminating evidence under the rug until all of the hullabaloo blew over.

Cops continued to say the case was still being investigated each time this newspaper reached out about it in November, December, and January. Authorities maintained that claim as recently as Monday, when one officer insisted “I’m looking at the complaint report, it says open,” after this reporter told him Gonzalez’s rep said the probe wrapped months prior.

“The police closed their investigation months ago is all I can tell you,” the spokesman said earlier that day.

But a legal expert attributed the discrepancy to nothing more than a lack of communication between two very busy offices.

“The DA is going to call the shots — they probably didn’t notify [police] that they are not prosecuting,” said attorney Daniel Flanzig, who represents cyclists across the city. “The police typically don’t know what the DA is thinking and have moved onto the next thing. It’s just lack of communication between the two offices.”

Mayor DeBlasio — who recently touted his ongoing Vision Zero initiative to eliminate all traffic-related deaths by 2024 with the announcement that 2017 had the city’s fewest number of traffic fatalities since officials started keeping track in 1910 — stands by the district attorney’s decision, and is working to improve safety regulations on private-trash collecting, according to a spokesman.

“We’re not going to second-guess the prosecutors and investigators who have access to all of the facts,” Eric Phillips said in a statement. “Instead, we’re working on cracking down on unsafe driving and better regulating the private-sector carting industry.

The Ramirez family’s attorney did not respond to requests for comment by press time, and police didn’t respond to requests for the crash-investigation report or other evidence, including the surveillance video, now that the case is closed.