Michael Wierciszewski, 25, was arrested by borough police after the victim told them he lunged at her with a knife while trying to kill her at the family’s Jackson Street residence on Nov. 24, 2021.
A search of the home turned up the improvised device, along with a Century Arms RAS 47 rifle that had been modified to remove the stock and accommodate a silencer, authorities said at the time.
The victim also turned over her cell phone, which they said Wierciszewski damaged as she recorded him threatening her.
A grand jury later indicted Wierciszewski on charges of aggravated assault, making terroristic threats, evidence tampering, creating a risk of widespread injury or damage and various weapons counts, including illegal possession of an assault firearm, Passaic County Prosecutor Camelia M. Valdes said.
He was also charged with illegal possession of the silencer, the magazine, metal knuckles and “explosives or bombs for an unlawful purpose,” the prosecutor said.
Wierciszewski was originally held in the Passaic County Jail but was later transferred to the Bergen County Jail, where he has remained since early February, records show.
Rather than risk the consequences of a guilty verdict at a trial, he took a deal from prosecutors.
Wierciszewski pleaded guilty on Wednesday, Dec. 21, to aggravated assault and possession of both the assault weapon and pipe bomb in exchange for what prosecutors said would be a five-year sentence.
Under the terms of the deal, Wierciszewski will have to serve 42 months of that sentence before he’ll be eligible for parole.
Valdes credited members of her office, Wanaque police, the Passaic County Sheriff’s Bomb Squad, the New Jersey State Police Ballistics Unit, the New Jersey Department of Labor and the FBI with the investigation leading to the plea secured by Passaic County Senior Assistant Prosecutor Timothy Kerrigan.
Superior Court Judge Marilyn Clark scheduled sentencing for Jan. 25, 2023 in Paterson.
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