abc7ny.com

A 16-year-old boy is in police custody after he allegedly shot and killed three family members and a family friend in New Jersey about 15 minutes before the new year, authorities said Monday.

The teen — who is not being named — allegedly used a a semi-automatic rifle to fatally shoot his parents, sister, and a family friend, Monmouth County Prosecutor Christopher J. Gramiccioni said in a statement. He was arrested without incident and is expected to be charged as an adult with four counts of murder.

The weapon used was legally owned and registered to a family member, officials said. No motive has been revealed and the case is being investigated as a domestic violence incident.

The suspect's brother and grandfather were able to get out of the house unharmed, Gramiccioni said in a press conference. Those killed include the boy's father Steven Kologi, 44, mother Linda Kologi, 42, sister Brittany Kologi, 18, and family friend, Mary Schultz, 70.

"It’s a terribly tragic incident," Gramiccioni said.