For nearly 40 years, Kathleen Flynn’s murder has haunted Norwalk, Connecticut. She was 11 years old, newly in middle school, walking home on a familiar path when she was attacked and killed.

One spring evening in 1987, a college student got into a green car in Plymouth, New Hampshire and vanished.

His friends believed he was coming back. His family knew he would have called if he’d left on his own. But he was gone, and the man believed to be with him on the night he disappeared had a long history of run-ins with the law.

For more than 30 years, Pam Williams believed she knew how her brother died. She was told it was a medical event.