David died only a month ago from a gunshot wound, and Mindy apparently changed her story about what happened.
"At first, she said she hadn't heard the gunshot because the TV was too loud. Then, she said she had heard the gunshot," says a law enforcement source.
"So obviously there were a lot of questions, and the Sheriff was asking for clarification," the source continues.
However, any lingering questions will no longer be able to be answered, as Mindy herself died of an apparent suicide at age 37 on February 17.
"At no point did [police] tell her she was a suspect, and she wasn't officially one," says the source. "But she knew that some of her answers didn't stand up to questioning. She was very cooperative, but she just wasn't making a lot of sense."
Police have yet to determine the cause and manner of David's death, but they say that Mindy's cause of death "appears to be a single self-inflicted gunshot wound."