The Air Force is now investigating 28 basic training instructors for improper relationships and abuse of power involving 54 alleged victims from Lackland Air Force Base.
The latest Article 32 hearing marks the first time an instructor has been charged with assault and battery against male trainees.
Staff Sgt. Ryan Deraas is charged with pursuing sexual relationships with five female trainees in a brother flight, and with maltreatment and assault and battery of seven male trainees in his own flight.
The airmen testified that Deraas forced them to fill their canteens with toilet water, ordered them to drink copious amounts of water, and yanked them away from the urinals when he caught them in the latrine without permission.
"There were no injuries, although one airman said that he held it for so long that there was blood in the urinal," said Joint Base Spokesman Brent Boller.
The investigating officer will make a recommendation on whether Deraas should be court-martialed.
Five instructors have been convicted in the sex scandal so far and ten others have been charged in the still-widening investigation.