Forensic Files

In 1991, Massachusetts resident Richard Alfredo died of an apparent heart attack. No one thought foul play until police looked into the odd behavior of his girlfriend Christina Martin in the days before his death. Controversy surrounded the case for almost a decade, pitting competing teams of toxicologists against each other -- one claiming natural death and the other saying it was cold-blooded murder by poisoning. [also marked as S7:E31]