A Harlem man who’d argued with the couple upstairs for a decade over noise “snapped” on Friday, shooting them dead, lighting his own apartment on fire, and then fatally shooting himself in the head during a police standoff, neighbors and authorities said.

The suspect, Bruce Anderson, 59, had fought with his neighbors — Hampton Smith, 78, and Smith’s 62-year-old girlfriend, Yvette Rivera — for some ten to 15 years in their building on West 131st Street near Malcolm X Boulevard before unleashing bloody vengeance, neighbors said.

At around 2:45 p.m., Anderson shot the old man in the head in a first floor hallway, Chief of Manhattan Detectives Martine Materasso told reporters.

He then shot the old man’s girlfriend in the head in the hallway of the second floor, Materasso added.

Police rushed to the scene and found the gunman had locked himself inside an apartment on the first floor.

“Come and get it!” the suspect shouted at cops from inside the apartment.

Police called for backup from the NYPD’s emergency services unit and noticed smoke coming from inside the apartment, Materasso said.

Cops then burst into the room and found the man dead in his bathroom with a gunshot wound to the head.

Materasso said the fire made the investigation “chaotic to say the least.”

One firefighter suffered serious, but non-life-threatening injuries; a second suffered minor injuries.

The slayings may have been the culmination of years of the three fighting over noise, the building’s super said.

“He didn’t like noise. That’s what they were going back and forth about. The noise over his head. They would argue about it. He would threaten them about it. The police had been called numerous times,” longtime super Ronald Mitchell, 70, said.

“So he just snapped, I guess,” Mitchell added.

Police recovered two guns from the killer’s apartment, officials said.

Shocked neighbors remembered the slain couple as helpful and cheerful people.

“Anyone who would meet him would love him. If you needed anything, if anything was wrong, he was there. If your sink was clogged. If there was a mouse. Anything at any time he would help you,” building resident Paris Benton, 34, said of Smith.

“I feel heartbroken. I feel completely heartbroken. I don’t want to walk down this block and not see his face,” she added.

No other suspects are being sought, police said.