Alan Carnegie was a judge murdered in 2009.
Unknown to Carnegie, his wife, Rhonda, was carrying on an extra-marital affair with a man twenty years her junior. Knowing that there would be hell to pay if her husband ever found out, Rhonda decided to kill him rather than risk exposure and a messy divorce.
She gained her opportunity when mafia boss Salvatore Lucarelli was indicted. Because Carnegie was the designated alternate to hear the mafioso's case, she killed both the first judge, Clarence Stanton, and then her husband, to make both murders look like Lucarelli's work.
However, Adrian Monk eventually tracked down and identified Rhonda as the killer of both men.