A Falls Township police officer was justified in shooting a knife-wielding man after responding to a call about a domestic dispute in August, Bucks County District Attorney Matt Weintraub said Wednesday.

The officer, a 21-year member of the department whom authorities did not identify, shot Jorge Perez, 48, once in the chest during an altercation in the basement of Perez’s home in the 400 block of Federal Lane, officials said. Perez was pronounced dead at the scene by paramedics.

“I’ve spoken to Mr. Perez’s family to explain my decision. I’m heartbroken for them,” Weintraub said in a statement. “I am also saddened for the officers who were involved in this tragically fatal incident. We always wish for a different outcome in these situations, because there are no winners here.”

Weintraub declined to name the officers involved because they do not face criminal charges.

Police were called to Perez’s home on Aug. 29 by his teenage son, whose mother had asked him to summon help, according to Weintraub. The couple — who were not married, but had lived together for years — had gotten into an argument after the woman said she wanted to end their relationship.

The son later told police that his parents argued frequently, and that his father had previously said the only way he would leave the house is “5 (or 6) feet under,” according to investigators.

On that August day, authorities said, Perez grabbed a foot-long carving knife from the kitchen and took it to the basement, where officers found him.Perez told the officers he had gotten into an argument with his girlfriend, but wouldn’t say if anyone in the home had been injured, police said.

He tried to leave the room several times, despite being told to stay where he was, authorities said, and at one point, the officers began to physically restrain him. He then pulled the knife from his waistband and pointed it at an officer, threatening him with it, authorities said.

Perez ignored commands to drop the weapon and settled into an “attack stance,” according to prosecutors. The second officer opened fire, they said, hitting Perez once in the chest.

After the shooting, the officer who had been struggling with Perez told investigators he believed Perez “surely was going to stab him and was surprised that he had not been stabbed,” and that his partner had saved his life by firing the fatal shot, prosecutors said.