On December 3, 1998, Wisconsin police were called to the home of Mark and Julie Jensen. Mark said he found his wife dead in her bed. Initially, police suspected Julie died by suicide, but a letter she had previously written expressed her suspicion that Mark might kill her. A series of toxicology tests revealed there was small amount of ethylene glycol, the main ingredient in antifreeze, in Julie’s stomach. “48 Hours" correspondent Erin Moriarty reports. This classic "48 Hours" episode last aired on 9/6/2008. Watch all-new episodes of “48 Hours” on Saturdays, and stream on demand on Paramount+.