UNION — A 911 caller told police she heard five gunshots the night an off-duty Newark Police Officer shot and killed a man in an altercation at at a Union bar.

It's not clear if five shots were in fact fired — investigating authorities haven't released any information saying so, and the caller is the only of three in 911 recordings provided to New Jersey 101.5 to make that assertion.

"How do you know it's accurate? I don't know five shots were fired," Newark Fraternal Order of Police President James Stewart Jr. told New Jersey 101.5 Monday.

Stewart offered little comment on the situation, other than to refer back to a statement he'd made earlier to New Jersey Advance Media: "It is our belief the entire incident is captured on video and when the investigation is completed it will show he was justified in his actions."

Stewart, however, told New Jersey 101.5 Monday that he has not seen video of the encounter.

But even if five shots were fired, former Morris County Prosecutor Robert A. Bianchi said he'd want to know more before making any judgments about what that could suggest. Bianchi. who is now in private practice in West Caldwell, has no direct knowledge of the case.

"Are you talking about boom-boom-boom-boom or are you talking about boom-boom (pause) boom? I know it sounds crazy but this could be indicative of a burst of a shots," Bianchi said.

Bianchi, who is now in private practice in West Caldwell, said there's a key principle police are taught — don't pull out a gun unless you intend to "eliminate the threat." He said that officers are trained to aim center mass and to shoot to kill, "otherwise you shouldn't be shooting."

Bianchi recalled a case in which the succession of shots was important and exonerated the officer. "It showed he shot a couple times, the threat was not neutralized, he fired more rounds."

Bianchi said an officer may pull a weapon as a show of force, to communicate to the aggressor, "back down." But the former prosecutor said if the officer, "doesn't believe they have the ability to use deadly force, at that point in time they have to re-holster their weapon."

"It's not that I'm gonna shoot you but I'm pulling the gun out as a way of saying 'hello, stop what you're doing," he said.

Michael Gaffney, 37, was killed before closing time May 13 outside Paddy's Place after he and the cop got into what authorities have only described as an altercation. Gaffney was unarmed.

Authorities have not said who instigated the altercation, or how it developed prior to the officer using his service weapon.

Several of Gaffney's loved ones have thrown their support behind a petition for a law to keep off-duty police from entering bars with their service weapons, intending to drink.

Authorities have not said if either party was intoxicated in the altercation.

No state law prevents a person with one of New Jersey's elusive concealed carry permits from entering a bar or restaurant that serves alcohol, and no state law prevents a legal gun owner from handling a firearm while drinking.

A federal law giving law enforcement officers the right to carry their guns into other states without first obtaining permits from those states, however, bars intoxication while carrying.

Even though the officer was not on duty, the Union County Prosecutor’s Office is investigating the incident the way they would any case in which an officer uses lethal force — as an officer-involved shooting. The officer has not been charged with a crime, and prosecutors have not publicly indicated whether they would present the case to a grand jury, which would decide whether to indict the officer on criminal charges.

Authorities have not released the officer's name.