Grand Canyon child abuse case trial starts PHOENIX, Feb. 15 (UPI) -- An Indianapolis man went on trial in federal court in Phoenix Wednesday, accused of putting his three grandsons through forced marches in the Grand Canyon. Christopher Alan Carlson has pleaded innocent to six counts of child abuse brought against him for allegedly twice making the boys, ages 8, 9 and 12, hike for miles without food or water in 100-degree heat last August, the Phoenix New Times reported. Authorities say a park ranger told Carlson to get the boys off the trails Aug. 15 after people complained the boys appeared worn out. Rangers then found Carlson and the boys on the trails again Aug. 28. When questioned separately from their grandfather, the boys allegedly told a ranger they'd been "hit, pushed, choked, kicked, pinched, squeezed and whipped" by Carlson. They alleged they were told to tell people they were "fine" if asked if they were all right. "They said they were not allowed to drink water on the hike down and resorted to drinking water from the Colorado River," the report stated. All three threw up on the hike multiple times. Two of the boys alleged Carlson had abused them at other times in other states and outside the United States, the newspaper said.