Gruesome stabbing rocks quiet Arnold neighborhood

The scene early Sunday evening in Arnold could have been from a movie.

In fact, Diana Rebold was known by neighbors to rent out her property on Liberty Avenue to filmmakers.

On one occasion, more than 100 people — including actors playing police — crowded around the Cape Cod home, according to neighbor Gene Musco, who was inside his home Sunday when sirens sounded.

“It made me think: ‘Are they filming again?’ ” Musco said.

But it was all too real. Neighbors told police they saw Brian Rebold stab his mother to death in the street.

Diana Rebold, 73, of New Kensington was pronounced dead about 7:30 p.m. by the Westmoreland County coroner, just feet from the white picket fence that surrounded her property.

In a criminal complaint, police detail how they observed gashes to her throat, back and head, caused by a knife found in the front yard of the home.

Authorities have yet to share a motive for the slaying, which took place about 5:30 p.m. Sunday. Arnold police Chief Josh Stanga described the stabbing as a “family incident.”

It’s unclear whether Diana Rebold ever lived at the Liberty Avenue home, but her son recently moved in after years of the house serving as a movie set and short-term rental for visitors through Airbnb or a similar platform, according to neighbors.

Liberty Avenue — part of “the Beverly Hills of Arnold,” as Musco put it — is a quiet part of town with a mix of longtime residents and young families, several of whom have children.

The area’s reputation made the stabbing even more shocking for residents, including Charisse Campise, who lives on Camp Avenue but has a clear view of Rebold’s property from her front yard.

“This is a really quiet place,” Campise said. “I’m still shaking from it.”

Feeling a bit under the weather, Campise opted to take a nap instead of trim her hedges late Sunday afternoon.

She woke up about 7 p.m. to emergency lights flickering outside her bedroom window and strangers in her front yard. By the time Campise emerged from her home, Diana Rebold had been covered with a sheet.

“If I had seen (the attack), I would have been out here with my 9 millimeter (pistol),” Campise said.

According to Campise, there had been an uptick in activity at the house in recent weeks, as though Diana Rebold and a man who often accompanied her were getting ready for something. Brian Rebold tended to hover around them without helping, according to Campise.

“He would just stand there in the corner and rock,” Campise said. “You can tell, OK, something is not right.”

Brian Rebold has a history of erratic and violent behavior, including a 2020 conviction for assaulting three people at the Valley Points YMCA in New Kensington. That same year, he pleaded guilty to another assault that took place while he was being held in the Westmoreland County Prison.

His Facebook page contains a series of dense ramblings about politics, music or some intersection of the two. One post, which doesn’t go into much detail, opens with what appears to be a warning: “Seems like everyone knows to stay away from me in no uncertain terms.”

As Arnold processes yet another tragedy, already having weathered two fatal shootings this year, Musco said he is worried about the future of the city where he has lived for more than 30 years.

The born-again Christian has been doing what he can to help.

“I was doing a lot of praying yesterday,” Musco said. “I’ve actually been praying for this whole area.”