NEW YORK - U.S. soldiers accused of murdering Afghan civilians for sport were members of a platoon where drug use was as common as the lack of supervision, officials said. The father of one of the soldiers charged in the killing of three Afghan civilians questioned why U.S. military commanders were unaware of problems leading up to the killings, The New York Times reported. "I just don't understand how this went so far," said Christopher Winfield, the father of Specialist Adam Winfield, one of the platoon members charged with murder. "I've been in management for 20 years; you know what your people are doing." Five platoon members of the Fifth Stryker Combat Brigade have been charged with murder in one of the most gruesome war crime cases to come out of nearly a decade of conflict in Afghanistan, the report said. Seven other members were charged with other crimes. However, none of the leaders of the 30-member platoon were charged or disciplined in the killings. Private Justin Stoner blew the whistle on the group's alleged drug use and sport killings, which were disguised to look like combat deaths. The platoon was sent to Forward Operating Base Ramrod about 50 miles west of Kandahar in 2009, where it was attached to a separate cavalry troop, further removing it from its regular chain of command, the newspaper said. Investigators didn't know the extent of problems in the platoon until early May, nearly four months after prosecutors say the first of three murders of Afghan civilians occurred. A member of the platoon said up to 20 of its 30 members regularly smoked hashish and drank alcohol they received in the mail.