Authorities responded to a home Tuesday morning on Justine Place in the Succasunna section of Roxbury Township for a welfare check.
The check was requested by one of the victim's friends after they were unable to reach them.
Officials said they found three people dead of gunshot wounds in the home in a suspected murder-suicide.
The family was identified as 57-year-old Peter Ventricelli, his 58-year-old wife Kellie and their 15-year-old son Anthony.
"This is a tragic murder suicide brought on by domestic violence," Morris County Prosecutor Robert J. Carroll said. "It is a heartbreaking loss for the Ventricelli family. Neighbors, schoolmates, friends and the Roxbury community as a whole are mourning this shocking and senseless loss of life."
Roxbury Public Schools sent a letter to families to share that a high school student was among those found dead.
Neighbors said the son was a popular sophomore and on the football team.
"I know that the people who know him were pretty devastated by it, they were acting totally different, they were empty, it's hard for anybody, even the seniors who might have known him even though he was a sophomore, it's tough to piece together in your own head," Stephen Kamp said.
Students decided to wear their school colors, blue and gold, in honor of Anthony on Wednesday. They remembered him as one of the nicest kids ever who always did what he could to help others.
The mayor released the following statement:
"The Roxbury Township Mayor and Council join the community as we try to cope with the terrible loss of three of our neighbors. We urge everyone to keep the victims and their family in their thoughts and prayers. We also wish to recognize and commend our Roxbury Police, as well as the Offices of the Morris County Sherriff and Prosecutor, and other assisting law enforcement agencies as they continue their investigation. The Township stands ready to assist in any way we can. We ask that all further inquiries be directed to the Morris County Prosecutors Office."
Detectives continue their investigation to determine how and why Ventricelli turned the gun on his family and took his own life.
ALSO READ | Asian woman speaks out after she and her son physically, verbally attacked in Queens
Victim speaks out after hate-filled attack in Queens
* Get Eyewitness News Delivered
* More New Jersey news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube