In the episode titled "Die Once, Die Twice," Susan Dey portrays Ellen Tanner, a young woman who is estranged from her parents and married to the unsavory Griff Tanner. Ellen Tanner decides to leave her husband one morning, she is surprised to find him coming home at the exact time she is walking out. When Griff pulls a knife on her and tells her that she can't leave him, Ellen runs to the bedroom to get a gun in order to defend herself. When she attempts to shoot her husband in self-defense, he knocks the gun to the ground. When the gun hits the floor, it accidentally fires and the bullet hits him. Ellen then runs off.
Matt Helm's lady friend is the lawyer who Ellen's family contacts. A private investigator (played by Howard Duff) is brought in after it is revealed that Griff was shot a second time after Ellen claims she left the scene. Ellen Tanner must eventually testify in court in an attempt to clear her name after being charged with first degree murder.
This was the final episode of Matt Helm that ever aired. It was an ABC show, just like The Partridge Family. This particular Matt Helm episode featured producer Mel Swope, who had previously produced 73 Partridge Family episodes. A couple months later in 1976, Susan Dey appeared on Good Heavens, another Mel Swope produced show.
Here are some images from the episode (click for full size):
