DATELINE WEEKEND MYSTERY PREVIEW: The Night of the New Moon

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A former marine, who once was the hero for a woman in an abusive marriage, is back on ‘Dateline.’ But this time, has his desire to help gone too far? Andrea Canning reports Saturday, May 18 at 9/8c. Airs at 1:30 a.m. MT and 1:32 a.m. PC.