poisonings captured in nancy's hair and the discovery of poison in vitamin pills found in the home were difficult to deflect. richard's girlfriend even testified, claiming richard lied by telling her that nancy had a rare and fatal blood disease. >> any time that you catch a defendant or any witness in a lie -- and that was a pretty big one -- and i don't think it's a coincidence that she was going to die from a fatal blood disease. i think that those things immediately begin to color their view of him, and he was a liar. he would lie. >> it took a jury less than three hours to convict richard lyon of first-degree murder. he was sentenced to life in prison. >> i worked lots of cases like this, and the question was always why not just a divorce. >> you know, they may be intelligent, but they're criminally stupid, and for good reason. and thank god they are, because we couldn't catch them. >> it was hard for me to believe