Two documentaries tell the story of Thomas Randolph, who was convicted in Nevada of murdering his sixth wife and the "hit man" he supposedly hired to kill her. HBO offers The Black Widower: The Six Wives of Thomas Randolph; Netflix has The Widower: 'Til Death Do Us Part.
The story gets its juice off the fact that three of Randolph's other prior wives died--one shot and two from cancer. Randolph was acquitted of conspiracy to kill Wife # 2 (the shooting), although convicted of tampering with one of the witnesses in that case. And the prosecution attempted to use evidence of Wife # 2 in the prosecution over Wife # 6. Here is the opinion of the Nevada Supreme Court on the case.
Neither doc is not great, as these things go. And the opinion tells a different story than the film. Still, worth watching for a couple of reasons: 1) the role of 404(b)(2) and 2) some good trial footage showing questioning of witnesses.