>> on the morning of valentine's day, prosecutors believe that the couple exchanged cards, and they argued about susan's not-so-veiled message inside. >> i don't believe i would have ever wanted to get this from my wife for valentine's day. it wasn't one of the more cheerful ones that you want. >> forcing an exchange of thoughts about one another, thoughts that maybe would have been better aired with a counselor in the room. >> the evidence suggests that dr. hamilton went to the hospital and performed one operation, and then returned home, possibly with an attempt toward reconciliation. prosecutors say the couple argued once again. in anger, hamilton took several neckties from his closet and strangled her.