Jennifer Sweeney (Khrystyne Haje) is the villainess from "A Very Fatal Funeral," episode 2.02 of Diagnosis Murder (airdate September 23, 1994).
Jennifer Sweeney is the secretary at the Malone foundation, who was seeking revenge on the group. She blamed them for the death of her father, who was waiting for medication that would have kept him alive, but the funds didn't go through, and she began her murderous spree by killing Elton Malone by poisoning one of the envelopes. Regarding the rest of the members, Jennifer killed each one with a poison dart, beginning with shooting Alexander Damon while attending Malone's funeral. The pattern continued with killing Christine Shaw at Malone's funeral, and Mort Slater at Shaw's funeral, leaving Norman Briggs as the final target.
Jennifer is revealed as the killer at Slater's funeral, when Norman fakes being shot to catch her. However, the weapon is not found in Jennifer's possession, so she is not arrested. In the final scenes of the episode, Jennifer resurfaced in Norman's office, with the weapon in hand, set to kill Norman. She is defeated in humorous fashion, as Jack Stewart angrily entered Norman's office, with the door knocking out Jennifer. Jennifer was presumably arrested off-screen.