Four innocent children were deliberately drugged and murdered by their own mother and grandmother in a sickening murder-suicide plot allegedly driven by a bitter custody dispute, according to investigators. The children, Harper Harmon, 13; Hudson Harmon, 11; and 10-year-old twins Gavin and Gracelynn Harmon, were found dead alongside their mother, Sarah Myers, 44, and grandmother, Amy Steadman, 64, inside Steadman’s apartment in Mechanicville, New York, on June 23. Investigators believe the children were murdered on June 10, nearly two weeks before their decomposing bodies were discovered during a welfare check. Now, toxicology results have revealed that diphenhydramine, the active ingredient...