Police shot and killed a man armed with a machete who confronted them Monday evening in Piscataway, New Jersey, authorities said.

Officers then went on to make a horrific discovery inside his home on River Road, finding the bodies of the suspect's mother and grandparents.

Gov. Phil Murphy called the incident "a tragedy at so many levels." State Attorney General Matthew Platkin called it "an unspeakable tragedy."  

The latest on the investigation

Police said they responded to a 911 call from the home at around 5:30 p.m. Monday, made by the suspect's father, the only survivor of the incident.

"You have to understand, there is a husband that's about to bury a wife, parents, and a son," Mayor Brian C. Wahler said.

According to the New Jersey Attorney General's Office, when Piscataway officers arrived on the scene, Jordan Barnes, 29, charged at them with the machete. The officers responded with stun guns, but they did not stop Barnes.

"Given the fact that the individual was carrying a machete and he had already committed three murders inside, you have to think about the officers' health and well being, too," Platkin said.

Platkin said New Jersey has a process when officers fire their weapons.

"Every encounter that involves law enforcement, we investigate independently. We release all the information as soon as we can, once we verify it and go through our process," Platkin said.

While the AG's Office looks into the police shooting, the Middlesex County Prosecutor's Officer is continuing its probe of the crime inside the home.

On Tuesday evening, the AG's Office identified the victims as Jeanmarie Barnes, 60, Richard A. Barnes, 86, and Brenda F. Barnes, 84. Each was said to have suffered multiple stab wounds.

Neighbors describe interactions with slain family members

Neighbors said they had never noticed anything out of the ordinary at the home. Many in the close-knit Piscataway community were still in shock Tuesday.

"It's just horrible and the fact that is happened in my backyard is even more terrifying," Keith Heron said.

"My wife said, 'Oh, when I was praying, I heard 'toot, toot,' like shots,'" Arshad Sidiki said.

Neighbors said the family appeared happy, adding they never witnessed any problems at the house.

"I spoke to the mother as late back as October for a brief moment and gave her a hug and said we should get together and that was the last time I saw her," Heron said.

Heron said he believes two sons were living at the home.

"They are always in the backyard. The son is always playing music," Heron said.

"It's very scary. I mean, we just share the fence and it was on the other side, usually weekends, I was lawn mowing and I see the people," Sidiki said.