The villainous Andrea Rivers
Andrea Rivers (Anne Lockhart) is the main villainess from "Murder in the Family," episode 4.12 of Diagnosis Murder (airdate December 12, 1996).
Andrea Rivers is a dispatcher for a trucking company, but unbeknownst to the company's boss, Dan Wolpert, she and her henchmen, Vince and Malcolm, accepted a lucrative offer to illegally dump toxic waste. As Andrea revealed later on, they were making $5,000 a week. One of the company's drivers, Bruce Hilton, videotaped one of the payoffs and blackmailed them for a bigger payout. Andrea had Bruce killed to keep him quiet.
Andrea's reveal came when she and her henchmen kidnapped Bruce's estranged wife, Carol Sloan (Mark's daughter and Steve's sister), knowing that Bruce bought a safe deposit box in her name. Carol was needed for Andrea to acquire the incrimiating videotape, and once she does, the evil Andrea planned to kill Carol; not wanting to risk letting her live due to the fact that her brother is a cop. Andrea is later apprehended by Steve and arrested, but not before she is on the receiving end of a right hook by Carol.