According to Traciy Curry-Reyes of the Movies Based On True Stories Archives, it's most likely based on this case.
http://www.examiner.com/article/the-preacher-s-mistress-true-story-movie-of-matt-baker-vanessa-buls
The articles say Waco.
shareIt says the exact same thing for Sins of A Preacher.
shareI saw the case of Matt Baker on one one of the crime channels and the story is not even the same. He killed his wife. The mistress knew nothing about it. I don't remember if he blamed it on her, but I don't think so and if he did, no one believed him. This is just another Lifetime movie.
shareI think it was just a fiction movie too.
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