Investigators believe the shooter to be the father of the two teens and the husband of the woman who was also shot and killed.
Police were called about a shooting on Chatham Place on Sunday at 9:30 a.m. When officers arrived, they found the parents and a teenager with gunshot wounds.
Officers say Justyna Nieroda, 41, Krzysztof Nieroda, 41 and Natalie Nieroda, 13 were pronounced dead at the scene. Sebastian Nieroda, 14, was in critical condition, but died hours later at University Hospital in Newark.
Authorities say Krzysztof Nieroda called a family member to tell them he had shot and killed his wife and children before then fatally shooting himself.
“There simply are no words to describe the trauma, heartbreak and sorrow that we are all experiencing,” said Mayor Derek Armstead in a statement.
Gov. Phil Murphy released a statement late Sunday afternoon saying that his staff was closely monitoring the shooting.
The community gathered outside the home Sunday night to light candles. Parents consoled their children as they grieved the loss of friends and classmates.