Suspected 1970s serial killer Bruce Lindahl has been identified as the culprit in a 1979 cold case murder through DNA evidence, Illinois authorities announced Wednesday.

In a surprising turn of events, the clothing 19-year-old Kathy Halle was wearing at the time of her mysterious disappearance March 29, 1979, has been linked to Lindahl. 

North Aurora Police Det. Ryan Peat said at a news conference that, on the night of her disappearance, Halle left her apartment to pick up her sister at the Northgate Shopping Center in Aurora, Illinois, but she never returned. Her body was found in a river several weeks later.

The case stayed cold for decades, until advancements of DNA testing prompted investigators to reopen the case.

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This undated file photo provided by the Lisle, Ill., Police Department shows Bruce Lindahl.  (Lisle Police Department via AP)

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

In 2020, North Aurora detectives met with the Lisle Police Department, and evidence was scrutinized from Halle's case and sent for additional testing, Peat said. The detective shared that the DNA was too degraded for a clear conclusion that Lindahl was responsible.

In 2022, the North Aurora Police Department learned that there was a box of evidence with Lindahl's belongings at the police department in Naperville, Illinois. Peat said that evidence showed that Lindahl often visited where Halle worked.

Peat said he turned to a new DNA tool, the "M-Vac," which can assist in collecting DNA from older cases.

In August, results showed that Lindahl's DNA was found on Halle's clothing. Investigators concluded that she was taken from her home and murdered that night in March 1979.

In March 1979, Kathy Halle disappeared en route to pick up her sister. (FOX 32)

"This was a long and challenging investigation, but today we’re able to give the Halle family the answers they’ve waited decades for," Peat said.

Lindahl, who is believed to have killed as many as a dozen women and girls, died in April 1981 while stabbing a man to death in Naperville. During the struggle, Lindahl somehow stabbed himself in a femoral artery. His body was found atop the victim’s.

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If Lindahl were still alive, he would have been charged in Halle's murder based on the new evidence, according to State's Attorney Jamie Mosser. 

"This case would have been charged in a court of law had Bruce Lindahl not died in 1981. His pattern of violence, combined with the DNA evidence we now have, leaves no doubt that he was responsible for Kathy’s tragic death. While we cannot prosecute Lindahl, the family now knows the truth, and justice — though delayed — has finally been served for Kathy," Mosser said during the press briefing.

Detective Ryan Peat said the DNA present on Halle's clothing matched Lindahl's. (FOX 32)

Halle’s family said in a statement that revisiting the case had been difficult, but they are grateful to have closure after 45 years.

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"Thanks to advancements in DNA technology and groundbreaking investigative tools, we are hopeful that other families won’t have to endure the same pain and uncertainty that we faced for so many years," the family said. "We extend our heartfelt thanks to the North Aurora Police Department and all the agencies and organizations involved for their dedication, persistence, and for never giving up, even when the odds seemed impossible."

Fox News Digital has reached out to the North Aurora Police Department for comment.

The Associated Press contributed to this report.