a potential clue. on the kitchen counter, they found the valentine's day card john purchased for his wife. >> and the card read, we are important loving caring people together. my life would be incomplete without you. i love you, john. >> the card susan gave to her husband had an entirely different message. >> one of the captions she had written herself said obviously, i bought this card before last monday. then as you open the card and begin to read the inside of it, she had written i bought this card two weeks ago so they don't seem as appropriate now. i love you. signed susan hamilton. >> police wanted to know what had happened two weeks earlier. dr. hamilton said they had a fight about money. but investigators found evidence there was more to it than that. >> there was accusations that he was having an affair with one of