Nearly 40 years after the murder of an 11-year-old Norwalk girl, the officer credited with solving the cold case took the stand in her accused killer’s trial.

Lt. Art Weisgerber, who secured the arrest of Marc Karun in 2019, testified at Stamford Superior Court on Wednesday, in what was the third day of evidence against Karun.

Weisgerber took over the case in 2002, 16 years after the crime that shook the city of Norwalk to its core and changed the way people lived. Parents no longer allowed their children to walk to school after Kathy Flynn was sexually assaulted and strangled while on her way home from Ponus Ridge Middle School on Sept. 23, 1986. The sixth grader's body was found in the woods off the path she took daily.

Weisgerber told the jury that when he was assigned to the investigation, he began by reviewing over 2,000 documents, such as police reports and interviews with about 175 people, including potential suspects. He also went through the physical evidence in the case. Weisgerber said fingernail scrapings from Kathy and hair found on her body had been submitted for microscopic testing in 1986, but DNA analysis wasn't available then. Once Weisgerber got on the case, he began resubmitting evidence for DNA testing every few years as the technology advanced, he testified.

Forensic examiner Jessica Manges was called to the stand next and took the jury through the results of specific testing done at Mitotyping Technologies in 2003. Manges said a pubic hair collected from Karun had the same mitochondrial DNA sequence as one found on Kathy's body. Manges testified that meant Karun and his maternal relatives could not be excluded as the source, though 97% of the population could, including another possible suspect in the case.

On cross-examination, Manges stated that mitochondrial DNA is not unique to an individual and doesn't give a one-to-one ID, like nuclear DNA. When pushed further, she estimated 17 million people could have that same sequencing.

Additional DNA testing is expected to be the focus of testimony when the trial continues on Thursday.

Karun, now 60, is charged with murder, murder with special circumstances and kidnapping. If convicted, he could spend the rest of his life in prison without the possibility of parole.

Karun was 21 at the time of Kathy’s death and was on investigators' radars early on because the crime resembled a previous sexual assault in which Karun was charged. In that case, the charges were reduced after the victim decided not to testify. That was just weeks before Kathy was killed.

Court documents show that in the years after, Karun was convicted of multiple sexual assaults, which police said were similar to Kathy's case. The likeness of those crimes, coupled with advancements in DNA technology, led to an arrest warrant for Karun in 2019.

The case took a while to get to trial, in part, because of superseding federal charges brought against Karun. Police said they found dozens of guns and nearly 15,000 rounds of ammunition at his home in Maine when they arrested him in connection with Kathy's death. Karun wasn't allowed to own any firearms because of his prior felony convictions. In 2024, he pleaded guilty to the federal charges, which allowed the homicide case to move forward.

In the run-up to the trial, Judge John Blawie denied requests for video and still cameras in the courtroom. The court rules state that in homicide trials involving sexual assault, the cameras will only be approved if the victim's family consents. At a hearing on the request, Stamford State’s Attorney Paul Ferencek told Blawie that Kathy's family did not.

PRIOR COVERAGE: Jury sees autopsy photos, hears testimony about how Norwalk girl killed in 1986 was bound, strangled