David Smith, ex-husband of South Carolina killer mom Susan Smith, has revealed what his ex-wife said to him after she drowned their two sons in a new 'Dateline' episode.

David Smith speaks out in an upcoming episode of NBC News' 'Dateline,' airing at 9 p.m. ET on Friday, Feb. 14.

Old photos of Patricia Altschul as a young mother to Whitney Sudler-Smith. She married her first husband, Lon Smith, who is ...