NORTH AURORA, Illinois — Bruce Lindahl, a 1970s serial killer who has been dead for decades, has been identified as the culprit in an unsolved 1979 murder, Illinois authorities announced Wednesday.

On March 29, 1979, 19-year-old Kathy Halle left her home to pick up her sister at the Northgate Mall in Aurora but never got there, North Aurora Police Detective Ryan Peat said at a news conference. Halle’s body was found in a river a few weeks later, Peat said.

The case remained cold for decades.

In 2019, police near Lisle, Illinois, reopened the 1976 murder case of 16-year-old Pamela Maurer and used DNA to link Lindahl to the murder, Peat said.

In 2020, North Aurora detectives working on Halle’s case met with Lisle investigators and the evidence was re-examined and sent for additional testing, Peat said. Although the DNA showed it was a mixture of two individuals, the DNA was too degraded for a working profile, Peat said.

Peat said that in 2022, North Aurora police learned that a box of evidence containing Lindahl’s belongings was found at the police department near Naperville, Ill., and that evidence showed that Lindahl had frequented the Northgate Mall, where Halle worked.

Peat later said he was investigating a new DNA tool: the “M-Vac” DNA wet vacuum that could help collect DNA from old cases.

In June 2023, North Aurora police took evidence from the Halle case to DNA Laboratories International in Florida to be analyzed with its new “M-Vac” tool, Peat said.

This August, Peat said, police received a report from the lab showing that “DNA that was approximately 9.4 trillion times more likely to originate from Bruce Lindahl was found on Kathy’s clothing.”

“We were able to conclude that Lindahl was responsible for Kathy Halle’s death,” Peat said, adding that police believe Halle was abducted from the parking lot of her apartment complex.

“Lindhal has been linked to many other cases in this area since that time period,” Peat added.

Lindahl may be responsible for the murders of up to a dozen young women, according to the Associated Press. Lindahl died in 1981 at age 29; He accidentally stabbed a major artery in his own leg while attacking an 18-year-old man in Naperville and bled to death, the AP said.

“If he had not killed himself in the act of a homicide, we would have authorized first-degree murder charges against Bruce Lindahl and gone to trial for Halle’s case,” said Kane County State’s Attorney Jamie Mosser.

Halle’s family said in a statement read on their behalf: “While re-examining this case has been incredibly difficult for our family, we are deeply grateful to finally have closure after 45 long years. Thanks to advances in DNA technology and groundbreaking investigative tools, ‘Other families’ We’re hopeful that he won’t have to endure the same pain and uncertainty we’ve faced for years.’