The trial begins Monday for the man accused of killing an 11-year-old Norwalk girl as she walked home from school nearly 40 years ago—a cold case that haunted the community for generations.

Marc Karun, now 60, is charged with murder, kidnapping and murder with special circumstances in the death of Kathleen Flynn, known as Kathy, in 1986. The murder with special circumstances charge is due to the victim being under the age of 16. Karun faces the possibility of life without parole. A jury of 12, plus six alternates, were selected for his trial.

On Sept. 23, 1986, Flynn’s mom reported her missing when she didn't return from school. The next morning, she was found strangled and raped in the woods, about 100 feet from the path she always took home.

Court documents show detectives had their suspicions about Karun early on, interviewing the then-21-year-old as a potential suspect 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 Flynn was killed.

In the years after, Karun was convicted of multiple sexual assaults, which police said resembled Flynn's case. The likeness of those crimes, coupled with advancements in DNA technology, led police to arrest Karun in June 2019 in Maine, where he was living.

It’s taken years for his case to go 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 Flynn’s death. Karun wasn't allowed to own any firearms because of his prior felony convictions. In 2024, he pleaded guilty to the federal gun charges, which allowed the homicide case to move forward.