Medical Detectives

In 1991, Massachusetts emergency personnel are called to the home of Richard Alfredo, who was slumped over dead of an apparent heart attack. No one thought foul play was a possibility until police looked into odd behavior of his girlfriend Christina Martin in the days before his death. Controversy surrounded the case for almost a decade, which pitted competing teams of toxicologists against each other -- one claiming the death was natural and the other saying it was cold-blooded murder.