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Inside the defense of Florida grandmother Donna Adelson. In Long Island, a judge's ruling on DNA ahead of alleged Gilgo Beach serial killer, Rex Heuermann's, murder trial. Plus, almost 21 years after her daughter was murdered, a mother hits the road to bring awareness to the unsolved case.

Blayne Alexander and Keith Morrison sit down to talk about his episode “ Under a Full Moon.” Shauna Tiaffay, a cocktail waitress on the Las Vegas strip, was found beaten to death in her home in September 2012.  Authorities wondered if the killing was a robbery gone wrong, until they got a tip that changed everything. It turned out that Shauna’s West Point graduate and EMT husband, George Tiaffay, had hired a hitman to carry out the crime. Keith and Blayne discuss how George was an unlikely killer and how his post-trial confession stunned his family. Later, Keith shares an extra clip from his interview with George’s sister. He and Blayne also answer your questions from social media. Listen to the full episode Under a Full Moon on Apple: https://apple.co/4lYmizk [https://apple.co/4lYmizk] Listen to the full episode on Spotify: https://open.spotify.com/episode/6GQUTnC0bvj7kYN9iS9dRG [https://open.spotify.com/episode/6GQUTnC0bvj7kYN9iS9dRG] To learn more about Dateline LIVE in Nashville on Sept. 28, and to get tickets, go here:https://www.nbcnews.com/dateline-event [https://www.nbcnews.com/dateline-event] If you or somebody that you know is experiencing domestic violence or relationship abuse, contact the National Domestic Violence Hotline at 800-799-SAFE (7233), text BEGIN to 88788, or visit thehotline.org

A Las Vegas cocktail waitress is found murdered in her home, leading authorities to wonder if there is a predator at large. Keith Morrison reports. Blayne Alexander and Keith Morrison go behind the scenes of the making of this episode in ‘Talking Dateline’ Listen on Apple: https://apple.co/46k2MbG [https://apple.co/46k2MbG] Listen on Spotify: https://open.spotify.com/episode/7g0KGFL590nFZYFTg7KMoU [https://open.spotify.com/episode/7g0KGFL590nFZYFTg7KMoU]

Two of Donna Adelson's children testify this week for the prosecution. In Northern California, a missing woman's husband is indicted for her murder more than a year after she vanished -- and a year and a half after he was indicted on felony domestic violence charges for an alleged attack on her. Plus, a former prosecutor on DNA's uses and pitfalls.   Find out more about the cases covered each week here: www.datelinetruecrimeweekly.com   To learn more about Dateline LIVE in Nashville on Sept. 28, and to get tickets, go here: https://www.nbcnews.com/dateline-event

A mother of two vanishes from her home, leading investigators to uncover a disturbing connection between her recent weight loss and her mysterious disappearance. Andrea Canning reports.