A sound he couldn’t ignore reverberated in his mind.

The courtroom drama surrounding a New Jersey technology executive accused of killing his brother and the brother’s family took a dramatic twist on Wednesday, reminiscent of a scene from “The Sopranos.” A pivotal witness recounted hearing gunshots and instinctively thinking, “Someone just got whacked.”

Dennis Corpora, an optician living next door to Keith Caneiro — who prosecutors allege was brutally murdered by his own brother, Paul Caneiro, in his Colts Neck estate — testified that he was jolted awake by the sound of five distinct gunshots on November 20, 2018.

“I was listening for any screams,” Corpora told the jury, his words tinged with a heavy Jersey accent. “I tried to rest again, but I knew something significant had happened at that exact moment.”

He took a screenshot on his phone to capture the ominous time but found himself unable to drift back to sleep, he shared with the court.

“I woke up, I heard the shots and I said to myself someone just got whacked,” he testified in Monmouth County Superior Court in Freehold. “Those are the words I said to myself. Those exact words.”

He then called 911 to report the gunfire  — dramatic audio that was played to the jury Wednesday.

“Do we allow hunting in the middle of the night?” he first asks the 911 dispatcher, to which she responds no.

When she inquired about how many gunshots were fired, he counted aloud — “Dun, dun, dun, dun, dun” — before she concluded it was five. 

“I don’t want anyone else getting shot,” Corpora told her before hanging up, according to the audio.

Corpora said he later phoned the emergency line again to ask about what the commotion ended up being.

“I called them back again because it was bothering me. I just knew something happened. I had that feeling that something happened,” he said.  

On the second call he was inexplicably told by a dispatcher, “It was unfounded. They didn’t find anything.”

During his testimony, Corpora said he sometimes heard gunshots in Colt’s Neck — possibly from hunters — “but they were not like this.”

He said he didn’t see anything, and could only hear the gunfire.

Caneiro is facing murder charges for allegedly gunning down his business-partner younger brother Keith, 50, fatally shooting Keith’s wife Jennifer, 45, and stabbing to death their children, 11-year-old Jesse and 8-year-old Sophia.

The alleged murders came just hours after Keith confronted his brother for stealing tens thousands of dollars from his trust.

Caneiro has pleaded not guilty.