Maybe he intentionally left his cell phone at whatever location that he claimed to be. In that scenerio, he wouldn't need to turn it off and if LE became suspicious of him and checked his cell phone pings, it would appear that he was where he said he was. For example, perp has an interview with LE for some reason and tells LE that on July 13 between the hours of 1:00 pm and 4:00 pm, he was in Waterloo shopping at the Billionaire-Mart and the adjoining Doghouse Depot and when he finished shopping, he went next door to the Howdy-Doody Bar. When LE checks his cell phone pings, the pings show his cell phone as being right in the area that he claimed. Perp wasn't there, though. Instead, perp went into the Billionaire-Mart around 1:00 pm, put his phone on mute, hid it in a restroom, and then, left to drive to Seven Bridges Park. He returned to Billionaire-Mart to retrieve his phone around 4:00 p.m.