Eric Liebert is the husband and later widower of Julie Liebert, a woman kidnapped and threatened with her life, leaving the couple's son Timmy abandoned with a note from the abductor. Eric saw Timmy's picture in the newspaper and immediately went to Special Victims while they were chasing the riddles the abductor left behind to save Julie in time.
The unknown abductor upped the anty by mailing a piece of Julie's ear directly to the squad. Unfortunately, detectives were too late and found Julie hanged to death, the killing being credited under RDK, a long absent serial rapist and killer. It was revealed a copycat, Humphrey Becker, was responsible, leading to Becker's arrest. (SVU: "Scavenger")