"VANISHED: MISSING IN MILWAUKEE," On ABC News' "20/20," Wednesday, January - Elizabeth Vargas Reports

If your daughter were missing and you thought you knew who was responsible, how far would you go in pursuit of a man police haven't charged with a crime and whose family says is completely innocent? Milwaukee area mother Karren Kraemer took her hunt to a level many may find over the top. It is an obsession that threatened to ruin her marriage and tapped out her 401K.

"I'll do anything to find her," Karren says about her daughter, Becky Marzo, "I just need to say goodbye." But is Becky dead? And if so, where is her body? Or maybe she's still somewhere out there with a new name and a new identity... having fled an abusive boyfriend.

Elizabeth Vargas reports on the emotionally haunting mystery of a loved one's disappearance combined with the chilling realities of domestic violence on a special edition of "20/20" entitled "Vanished: Missing in Milawukee," Wednesday, January 7 (9:00-10:00 p.m., ET) on the ABC Television Network.