Fairmount Park rapist identified after 20 years, police say

Philadelphia Police believe that a man who was arrested this week for allegedly slashing people with a machete in Pennypack Park is also the so-called Fairmount Park rapist, a previously unknown and long sought-after assailant who sexually assaulted four women — one of whom he killed — nearly two decades ago.

The stunning development came after investigators say they’d used genealogy tools earlier this year to finally identify 46-year-old Elias Diaz as a suspect in the decades-old rape cases. Still, police for months were unable to actually locate Diaz. Family members across the mainland U.S. and Puerto Rico had long been estranged from him and were not sure where he was. Some believed he could be dead.

Then, over the weekend, police arrested a man with the same name for the November assaults in Pennypack Park — crimes in which police said the assailant slashed his victims with a large knife while riding a bike.

Investigators quickly came to realize — through DNA testing and the details of their continued investigation — that the person now in custody was the same man who had eluded investigators and captivated Philadelphia for decades.

“It haunted people in this community, it haunted people in this department,” Interim Police Commissioner John Stanford Jr. told reporters Tuesday.

District Attorney Larry Krasner said the case demonstrated the continual advancement of technology in investigations, comparing the tactics used here to the methods used to apprehend suspects such as the notorious “Golden State Killer,” a serial rapist and killer in California, and Philadelphia’s own “Boy in the Box,” a murder victim whose identity had been unknown for decades.

Diaz is believed to have attacked and raped four young women between 2003 and 2007, all of whom were running or walking alone in secluded areas of a park. In one of the attacks in July 2003, he allegedly assaulted and fatally strangled Rebecca Park, a 30-year-old medical student. Her body was discovered four days later in a shallow grave, a few yards off the trail where she’d gone for a run.

A second set of DNA tests was expected to confirm Diaz’s role in those attacks Tuesday night, Stanford said, and prosecutors said they would approve charges for murder, rape, and additional offenses.

Police are not entirely clear where Diaz had been living the last two decades. They believe he has largely been homeless, drifting through the streets of Philadelphia, sometimes among the unhoused in Kensington. Most recently, they said, he was likely living in the woods of Pennypack Park; investigators on Tuesday found an area he was using for shelter.

Diaz’s first known victim was in April 2003, when a 21-year-old woman on a run near Kelly Drive and Fountain Green Road was attacked from behind, then raped at knifepoint, police said.

Three months later in July, police say, Diaz raped and strangled Rebecca Park. The Inquirer reported at the time that Park told her boyfriend she was going for a run on the wooded trail she frequented near her home. She didn’t return, and her body was found four days later, partially undressed and covered in leaves, about 30 feet from the trail.

On Oct. 25, 2003, police say, Diaz attempted to sexually assault a third woman at knifepoint on Martin Luther King Drive near Falls Bridge, but the 37-year-old jogger fought him off, suffering stab wounds to her neck, chest, and hand in the struggle.

Four years later, police say, a 29-year-old woman was walking in Pennypack Park when a man grabbed her from behind, dragged her into the bushes, then raped and robbed her.

The case has for decades stumped investigators, and left some across the city in fear. DNA from the victims and the circumstances of the attacks, led police to believe they were committed by a lone man.

For nearly 20 years, police only had a general description of what he looked like: a black-haired Hispanic male, about 5-foot-8, with a widow’s peak and bushy eyebrows. Some victims said that he had an earring in his left ear, and that he was seen riding away from two scenes on a purple bicycle.

Then, in 2021, police used DNA analysis to create a series of composite sketches of what he likely looked like, and released them to the public in hopes they could spur new interest in the cold case. Investigators also sent the DNA to a genealogy lab, which offered insight into his family history.

Deputy Police Commissioner Frank Vanore said detectives, in partnership with the FBI, sorted through more than 1,000 family members across the mainland U.S. and Puerto Rico. In April, they were led to a man named Elias Diaz, and he became their main person of interest.

Diaz had no clear family ties to Philadelphia, Vanore said, but had been arrested for drug possession in December 2007. Family members said he had been estranged for years; some heard he frequented the Kensington area and was homeless, Vanore said, while another said they heard he had overdosed.

“We had no idea if he was even still living,” Vanore said.

But recent developments make clear that he was — most recently living amid the brush in the park where, just last month, he is accused of slashing two people with a machete.

First, on Nov. 22, Stanford said, a man was riding a bike on the Pennypack Park Trail around 8:15 a.m. when Diaz rode up behind him and slashed him with a knife on the arms and hands.

Two days later, around 9 a.m., Stanford said, a man and a woman were walking together on the trail when police say Diaz approached them, again on a bike, and sliced the man with the blade on the arm and hands.

Then, on Dec. 6, a woman called police to report that a man on a bicycle had yelled at and tried to attack her on Nov. 25, but she fled unharmed.

Still, police went on to publicize information about the attacks, which they believed were committed by the same suspect. And on Dec. 17, Stanford said, police received a call about a man in the park riding a bike with a machete attached to it. An 8th District officer responded, found Diaz on the bike, and arrested him for attempted murder and assault.

Diaz refused to speak to detectives or identify himself, Stanford said. When they processed his fingerprints, they learned his name — and detectives then realized this was the man who they’d been searching for all along. A DNA comparison to the DNA collected from the rapes confirmed it, he said.

It was a remarkable advance in one of Philadelphia’s most notorious string of crimes.

Park, originally from Olney, Md., was in her final year at Philadelphia’s College of Osteopathic Medicine. She was remembered by her father in an interview at the time as a kind young woman who enjoyed spending time outdoors, and who was interested in soon starting a family with her boyfriend.

Her death devastated her loved ones.

“I’m studying meditation,” her father Sung Park said in 2003. “I think she is waiting somewhere for us.”

Sung Park died last year. His wife and son could not be reached Tuesday.