Police identify the Salt Lake City man allegedly stabbed to death by his stepson

Police on Monday identified a 54-year-old Salt Lake City man who was allegedly stabbed to death by his stepson over the weekend.

John Richard “Johnny” Postlethwait was found dead at a home near 700 East and 1700 South when police arrived at about 1 p.m. Saturday.

The victim’s stepson, 30-year-old Charles Anthony Petrie, was arrested and booked into the Salt Lake County jail on suspicion of first-degree felony murder, where he was being held without bail.

A witness who heard the Postlethwait screaming, ran into his bedroom and saw Petrie on the bed pushing a knife into Postlethwait’s chest, according to a probable cause statement filed by police in 3rd District Court.

Postlethwait told the witness, “He’s f---ing killing me, he’s killing me,” and the witness wrestled Petrie off of him, according to the statement.

Police observed that Petrie had blood on his hands, shirt and shoes, the statement says.

Formal charges had not been filed as of Monday.

On Friday, a day before the slaying occurred, Petrie was released from jail after serving 10 days in jail on a 2016 assault case.

According to court records, Petrie was accused of choking his brother’s girlfriend in April 2016 while the couple’s child was present in the home.

Petrie pleaded guilty last June to third-degree felony aggravated assault, and three other counts were dismissed, including third-degree felony domestic violence in the presence of a child.

The plea was to be held in abeyance for two years, meaning if Petrie met certain conditions during that period, the case would be dismissed.

But Petrie did violate the conditions, including by failing to report to probation officers, failing to complete mental health and substance abuse evaluations, and by giving authorities a bad home address, court records show.

After he was arrested on a warrant in December, a hearing regarding the violations was set for Jan. 12.

When Petrie failed to appear at the hearing, another warrant was issued and he was booked into jail on Jan. 16.

A judge on Friday terminated the plea in abeyance agreement and entered a guilty plea to the aggravated assault count.

The judge suspended a potential zero-to-five-years prison term and placed Petrie on probation for three years, which includes many of the conditions that were part of the plea in abeyance.

The judge also gave Petrie credit for the 10 days he had just spent in jail and ordered him released from jail.

Postlethwait had served six years in at the Utah State Prison, beginning in August 2002, in connection with a 2001 conviction for first-degree felony attempted aggravated sexual abuse of a child.

He was paroled in August 2008 and discharged from parole supervision last July, according to the Utah Department of Corrections.

Last August in connection with the case, the Utah Board of Pardons and Parole ordered Postlethwait to pay $3,675.56 in restitution to the state Office for Victims of Crime, court records show.