The trial for a nanny accused of fatally stabbing her young charges has begun, and the mother who found the grisly scene has testified in murder trial of Yoselyn Ortega. In 2012, Ortega allegedly killed Lulu, 6, and Leo Krim, 20 months, a crime her attorney plans to argue she is "not responsible by reason of mental disease or defect." She had worked for the Krims for about two years when she was reportedly found trying to slit her own throat as the children lay dead in the bathtub. #InsideEdition