The most decorated cop in NYPD history has died decades after patrolling a notorious Bronx neighborhood where he earned a reputation as a “unique” leader who could “smell a gun from a block away.”

Legendary Lt. Robert DiMartini, who retired from the NYPD’s Street Crime Unit in 1989, died on June 12 from the effects of a stroke, according to friends. He was 80 years old.

“He was a police officer … a first-class leader,” Peter Pranzo, a retired lieutenant who worked with DiMartini, told the New York Post on Monday, calling his late colleague “a legend of the NYPD.”

DiMartini, who joined the police force in 1969, owned more than 500 medals at the time of his death, making him the “most decorated officer in NYPD history,” Pranzo said.

“We didn’t wear our uniforms very often, but seeing Bobby with all his medals was special,” Pranzo added.

DiMartini worked as a plainclothes police officer in the 1970s and 1980s, serving primarily in the 41st Precinct in the South Bronx, known as “Fort Apache” because of its alarmingly high crime rate.

His fearlessness was matched only by his uncanny ability to detect a crime and act quickly.

“Good cops thought ahead, and that was Bobby. He had tremendous legal knowledge,” Pranzo said. “And he knew his surroundings so well – you could drop him off in any part of town – he was a survivor and a worker.”

DiMartini was best known for his sixth sense, which enabled him to track down criminals carrying illegal weapons in the Bronx and other parts of the city.

Pranzo said his colleague “could smell a gun from a block away.”

In the mid- and late 1980s, Pranzo and DiMartini worked in the street crimes unit, which focused on the Bronx but also operated in other parts of the city, where they worked in plain clothes or undercover.

DiMartini headed the Bronx robbery unit from 1980 to 1985, when his two-man teams, dubbed “Supersquad Six” by newspapers, averaged an incredible 15 arrests and five weapons seizures a day.

DiMartini “probably took more guns off the streets than any other cop in the history of American policing,” Mike Bosak, a retired NYPD sergeant and unofficial historian of the police department, said in 2015.

When The Post interviewed him this year, DiMartini had received 476 NYPD awards – making him the most decorated cop in the police department’s history.

“In his final years, he was finally recognized as the hero he was,” Pranzo said of the NYPD. “In the last years of his life, he received more accolades than he ever had in his profession.”

His daughter, Liza DiMartini, called her father a widely respected “hero” in a tribute she wrote earlier this summer.

“Dad was my hero before he became the NYPD hero you all know and love him for. He was so much more than just a cop,” she wrote on a GoFundMe page.

“I listen to the stories and hear all the memories from people he worked with, people he grew up with, and sometimes people he was just friends with. Even people who didn’t agree with him.”

“We all had one thing in common: we loved and respected him, no matter what his views were or what he did for a living.”

Pranzo described DiMartini’s reputation as “unique.”

“He was a very, very strong family man. He loved his family as much as he loved his job, the NYPD – he was so dedicated,” Pranzo told the Post.

“He was a hero. And that’s not something you can say about many people.”