Luis Frias makes John Walsh's most-wanted list after allegedly stabbing his common-law wife to death in front of their children; Callahan Walsh explores the case of Harold Butch Knight, who left a trail of clues after confessing to killing his wife.

John Walsh reveals that a single mother is far from safe with ex-Marine Raymond R.J. McLeod who initially seemed like a knight in shining armor; Callahan Walsh discovers how rapper Maurice Nesbitt's constant abuse of his girlfriend turns deadly.