HBO's The Black Widower: The Six Wives of Thomas Randolph tells 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. The story gets its kicks off the fact that three other prior wives died. Randolph was acquitted of conspiracy to kill Wife # 2 (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.
The 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.