A New Jersey man killed his wife and two kids Sunday and then called a relative to admit to the murders before turning the gun on himself, police said Monday.

Deputies who responded to the family's home in Linden on Sunday morning found the bodies of 41-year-old electrician Krzysztof Nieroda, his wife, 41-year-old Justyna Nieroda, and the couple's 13-year-old daughter Natalie Nieroda. The couple's son, Sebastian Nieroda, 14, was found alive in critical condition and was pronounced dead later at University Hospital in Newark, NY Post reported.

When cops found the dead bodies, Krzysztof had the murder weapon in his hand. After fatally shooting the family members, Krzysztof called an unidentified relative on phone and confessed to the killings, police said. He then shot himself in the head.

Investigators have not revealed the possible motive behind the gruesome murder-suicide.

The family moved into the neighborhood in 2007, and Justyna was running a salon out of the house. The neighbors were shocked to learn the tragic news and remembered them as a friendly couple.

"They're a normal family. That's why it's impossible to believe.They go camping every long weekend with a trailer they hook up to their car. They recently renovated their kitchen, and he invited me over to show it to me," a neighbor reportedly told the outlet.

"Wonderful kids. The whole family was really nice," a neighbor, Roman Zygadlo told CBS News.

Sebastian was an 8th-grade student at McManus Middle School and Natalia studied in the 7th grade.

Meanwhile, the Linden School District arranged grief counselors for students and the staff of McManus Middle School and the elementary school the two children previously attended.

"Any student death affects us all. But we will never become so accustomed to a loss like this that we can't respond with empathy, understanding, and care. We will fully support each other during these difficult times. Let us all work together towards that end," Rocco G. Tomazic, Interim Superintendent of the School, said in a statement.

The incident was investigated by the Union County Prosecutor's Office along with the city police, reports said.

"In tragedies of this magnitude, there are no words that can heal, nor explanations that can serve to make sense of them to the public. Our thoughts go out to the family and friends of these victims and to the Linden community as a whole in the wake of this horrible event," Union County Prosecutor William Daniel said in a statement.

If you have thoughts of suicide, confidential help is available for free at the National Suicide Prevention Lifeline. Call 1-800-273-8255. The line is available 24 hours a day.

Police lights
Representation. Lights of a police car. MagnusGuenther/Pixabay