In May of 1990, a clown carrying balloons and flowers walked up to Marlene Warren’s home in an affluent southern Florida suburb and shot and killed the 40-year-old mother at point-blank range when she opened the door. Friends and family were quick to raise suspicion about her husband, Michael Warren, but his denial and airtight alibi brought investigators back to square one, leading to a 33-year journey to solve the case. Finally, just weeks ago, in April of 2023, Michael’s second wife, Sheila Keen-Warren, pled guilty to second-degree murder. In a new “20/20,” contributing anchor Deborah Roberts takes a look at the decades-long case and details how authorities finally brought the killer to justice.