The 16-year-old boy who allegedly shot and killed his parents and 18-year-old sister required special care, a neighbor told a local news outlet.

As CrimeOnline previously reported, Steven Kologi, 44, Linda Kologi, 42, Brittany Kologi, 18, and family friend Mary Schultz, 70, were shot and killed just before midnight in the Kologi’s home in Long Branch, New Jersey.

Police said they believe a 16-year-old male family member is responsible for the killings, and used a semi-automatic rifle to shoot his relatives and a family friend who lived in the home. According to NJ.com, the rifle was legally registered to a resident of the home.

Monmouth County Prosecutor Christopher J. Gramiccioni said in a news conference on Monday that the quadruple homicide is being treated as an isolated domestic incident, and that there is no threat to the public. Authorities reportedly arrested the suspect without incident after they were called to the home on New Year’s Eve.

A neighbor told the news outlet that the teen suspect, who has not been identified, said that he required special assistance and care in his home, and did not attend the same public schools as his siblings.

“But he was fully functional and comprehended what we were saying,” Jalen Walls told NJ.com.

The suspect’s brother and grandfather were also at the home on Sunday night, but reportedly fled from the shooting without any injuries.

The teen suspect is scheduled to be arraigned as an adult on Monday, and is facing multiple murder charges and a weapons charge.

Authorities have not commented on a possible motive for the deadly shooting.

This is a developing story and will be updated as more information becomes available.

[Feature image: Facebook/Kologi family members]