'People Magazine Investigates' Examines How Authorities Cracked 1991 Cold Case Murder of Pa. Mom

The morning of April 19, 1991, was a typical one for the Hibbs family from the quiet town of Croydon, Pa.

Twelve-year-old David Hibbs got up and got ready for school.

"My mom had a couple cups of coffee in the morning like she always did," he recalls.

After spending a few minutes playing with the family's new puppy, David jumped on the bus and headed off to school.

He would never see his mother, Joy Hibbs, 36, alive again.

When he got home from school that day, he found his house in flames — and his mother was inside.

"I opened the back door and was met with a plume of flames," David recalls. "I remember screaming, 'Help! Help! My mom's in there! I need help!'"

His mother, Joy Hibbs, had died.

But it wasn't the fire that killed her, authorities said. They later learned she was murdered — and that the killer had allegedly set the fire to cover his tracks.

For 31 long years, the case went cold — until recently, when authorities arrested the man they allege killed the beloved mother of two.

The haunting case is the subject of next Monday's episode of People Magazine Investigates, "American Nightmare," which airs on July 25 at 9 p.m. ET on Investigation Discovery and also streams on discovery+. (An exclusive clip is shown below.)

The episode details how authorities tracked down Joy's killer three decades after she was murdered.

On May 25, Bucks County District Attorney Matt Weintraub announced that Robert Atkins, 56, of Fairless Hills, had been arrested and charged with first-degree murder, second-degree murder, arson and robbery in connection with Joy's death.

"After the fire was put out, Joy Hibbs was discovered dead in her son's bedroom," Weintraub said at a May 25 press conference. "She was stabbed repeatedly, she had fractured ribs, and was likely asphyxiated."

She was strangled with an electrical cord found amid the home's charred remains, according to authorities.

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Atkins had spoken with authorities twice over the years, telling them he was a "confidential" police informant who was working with the Bristol Township Police Department when Hibbs was killed, according to the criminal complaint.

During the investigation, Atkins' ex-wife testified before a grand jury and alleged Atkins had come home covered in blood on the day of Hibbs' murder.

Atkins also allegedly "took money from her and intentionally set the family home on fire in an attempt to cover up the murder," Weintraub said in a statement.

Weintraub credited People Magazine Investigates with helping to spark renewed interest in the case, which led detectives to take a fresh look at the slaying.

Weintraub also noted that from the beginning, Hibbs' family never gave up on finding her killer.

"It was always the Hibbs family's undying, unwavering hope in achieving justice," he told PEOPLE.

Atkins remains held without bond in the Bucks County Correctional Facility. He has not yet entered a plea. He is scheduled to appear in court for a preliminary hearing in September.

His attorney had no comment when contacted by PEOPLE.

See more on how police cracked the cold case murder of Joe Hibbs on People Magazine Investigates ("American Nightmare"), airing Monday, July 25 at 9 p.m. ET on Investigation Discovery and also streaming on discovery+.