The 16-year-old has been charged as an adult with four counts of murder, prosecutors said.
Watch video
UPDATE: Mystery shrouds teen's alleged killing of parents, sister, family friend
A 16-year-old armed with a semi-automatic rifle shot and killed his parents, his sister and a family friend just before midnight on New Year's Eve in Long Branch, authorities said Monday.
The teen, whose name was not released because he is a juvenile, has been charged as an adult with four counts of murder and a weapons charge.
"It's a terribly tragic incident," Monmouth County Prosecutor Christopher J. Gramiccioni said during a press conference in Long Branch.
The teen was taken into custody without incident, Gramiccioni said. Law enforcement officials would not comment on the teen's possible motive for allegedly shooting his family.
Neighbors and friends said the 16-year-old had special needs, did not attend regular public schools and was cared for by his mother. Police said there was no history of domestic violence at the house.
The 16-year-old killed his father Steven Kologi, 44, mother Linda Kologi, 42, sister Brittany Kologi, 18, and family friend, Mary Schultz, 70, of Ocean Township, Gramiccioni said.
Two other family members were also at the house, but were not hurt, prosecutors said.
"The grandfather of the suspect as well as the brother of the suspect thankfully left the home," Gramiccioni said.
A 911 call reporting the shooting was made at 11:43 p.m. from inside the duplex on the 600 block of Wall Street, Gramiccioni said.
A Century Arms semi-automatic rifle was seized at the scene, Gramiccioni said. The rifle was legally owned and registered to a resident of the house, though authorities did not say who owned the weapon.
The 16-year-old is being held at the Middlesex Youth Detention Facility and will have his first court appearance at 10 a.m. on Tuesday, according to a spokesman for the Monmouth County Prosecutor's Office.
The shooting is being investigated as an isolated domestic violence incident, and there is no danger to the public, Gramiccioni said.
Neighbors said they were shocked by the deaths in the suburban Jersey Shore neighborhood on the border of Long Branch and West Long Branch.
Jalen Walls, a neighbor who went to school with Brittany Kologi, said his mother woke him up Monday morning to let him know about the shooting at his friend's house two blocks away.
Walls, who frequently went to the Kologi's house, said their 16-year-old son required special assistance and was cared for by his mother. The teen did not attend Long Branch High School, where his brother and sister graduated.
"But he was fully functional and comprehended what we were saying," said Walls, 18.
Brittany Kologi had recently finished her first semester as a freshman at Stockton University in Galloway, where she was a heath sciences student and lived on campus, according to the school.
"We are shocked and saddened by the reports of the death of freshman Brittany Kologi under such tragic circumstances," the school said in a statement, adding that counseling staff are available for her friends and classmates at Stockton.
Gary Patel, owner of the Welsh Farms convenience store across the street from the home, said the Kologi family frequently shopped in his store. Linda Kologi regularly purchased lottery tickets, he said.
"She was a nice lady. She was always smiling and very happy," Patel said.
Investigators were still at the scene, walking in and out of the family's brick duplex, on Monday morning.
Tributes to the family were posted on social media by stunned friends.
"I love you, Linda and Brittany with my entire heart. You all made up the best years of my life, I'm so blessed to have had the time i did with your family," read one Facebook tribute from a friend who grew up with Brittany.
Another friend wrote that Steven Kologi was loved by his friends and teammates on his softball team.
"For this to happen to this man and his family just simply can't be explained. I've known Steve 'Kujo' Kologi for decades and I can say this, I've never had an argument or disagreement since I've known him," according to another Facebook tribute.
Staff writer Erin Banco contributed to this report.
Kelly Heyboer may be reached at kheyboer@njadvancemedia.com. Follow her on Twitter @KellyHeyboer. Find her at KellyHeyboerReporter on Facebook.