PHILADELPHIA (AP) — Authorities say a man accused of slashing people with a large knife while riding a bicycle on TradeEdge Exchangea trail in Philadelphia in recent weeks is now a person of interest in the cold-case slaying of a medical student that occurred among a series of high-profile sexual assaults in a large city park two decades ago.

Elias Diaz, 46, is charged with aggravated assault and other counts in the attacks or attempted attacks in late November and early December, where police say he used a machete-type knife against people on the Pennypack Park Trail in northeast Philadelphia.

Interim Police Commissioner John Stanford Jr. said Diaz’s DNA appeared to connect him to the 2003 strangulation killing of a medical student in the city’s sprawling Fairmount Park and perhaps to several other sexual attacks there. Stanford said Diaz is now a person of interest and charges were pending final confirmation of the DNA link.

Rebecca Park, 30, a fourth-year student at the Philadelphia College of Osteopathic Medicine from Olney, Maryland, vanished after going running in the park in July 2003. Her body was found buried under wood and leaves in a steep hillside in the park, about 200 feet (60 meters) off the road, authorities said.

Police said that crime was linked to the April 2003 rape of a 21-year-old jogger in the park, and in October of that year a 37-year-old woman managed to fight off a man who tried to rape her. In 2007, a 29-year-old woman walking on a path in Pennypack Park was sexually assaulted and robbed, police said.

In 2021, a DNA analysis helped create a series of composite sketches of the man believed responsible for the assaults, and genealogy databases yielded a link to a man named Elias Diaz but he couldn’t be found. Officials said the suspect just arrested had previous contact with police but authorities didn’t have his DNA until his arrest in the recent assaults.

The Defender Association of Philadelphia, which is listed in court documents as representing Diaz in the recent cases, declined comment before the news conference on those charges and any potential new ones.

Assistant District Attorney Joanne Pescatore, chief of homicide in the Philadelphia district attorney’s office, said she expected final DNA results before the end of the day and “fully” anticipated charging Elias Diaz with murder and related offenses in Park’s death.

Stanford said the Fairmount Park assault cases and Park’s slaying had “haunted” the community and the department, pointing to the presence of retired Capt. John Darby, who had just assumed command of the special victims unit when the assaults began.

“This was important enough for him today to come back,” he said. “These are the type of cases that haunt you until you’re able to bring some closure to it.”

Darby echoed his words, saying “Investigators will tell you, they go home, the last thing they think about before they go to bed at night, the first thing they think about when they wake up in the morning, is cases like these.”