An investigation has concluded that deadly use of force by the Monmouth County SWAT team was justified during a standoff with Scott McAllister at his rented Middletown home in May.

Police say McAllister, 39, was holding his 13-month-old son at knifepoint inside his rented house on Bayside Parkway for several hours before the county Emergency Response Team stormed the dwelling.

According to a report by the Attorney General’s Shooting Response Team, the incident started when Middletown police responded to a 911 call regarding a domestic dispute.  McAllister was locked inside the house. His girlfriend told police that she had fled the dwelling, McAllister was drunk, he had beaten her, and he threatened to use a knife on the baby, the AG's office said.

During attempts to negotiate, McAllister called 911 and warned that "people would die" if police didn't pull back — and he threw beer bottles at officers, it said.

The situation climaxed about five hours after it erupted, when two teams of SWAT members barged into the home. One team went in the front door to take down McAllister while another team attempted to rescue the infant from an upstairs bedroom, the AG's office said.

McAllister made his way to the bedroom and pointed a large knife at an officer holding the infant making a slashing motion, the AG's office said. After ignoring orders to put down the knife, McAllister moved towards the officer and made movements as if he were going to slash the officer, the office said.

The officer fired his service rifle at McAllister, causing him to fall down a ladder, and killing McAllister. The baby was not hurt.

The report concluded that the officer used an "acceptable level of force" in pointing and firing his weapon at McAllister. The report states that "an officer may use deadly force in New Jersey when the officer reasonably believes it is immediately necessary to protect the officer or another person from imminent danger of death or serious bodily harm."

The Attorney General's Shooting Response team consists of deputy attorneys general, detectives of the Division of Criminal Justice (DCJ) and the New Jersey State Police Major Crimes Unit. It is employed for investigations of shootings involving state and county law enforcement.

Tom Mongelli contributed to this report

Dan Alexander is the Digital Operations Specialist for NJ101.5 and Townsquare Media NJ. He can reached via email at dan.alexander@townsquaremedia.com, on Twitter @DanAlexanderNJ and at 609-359-5358