The alleged pedophile “LuvEmYoung” had worked to stay anonymous in the chatrooms where he bragged about sexually abusing children. A criminal affidavit said he covered his tracks by using TeleGuard, an encrypted Swiss messaging app, to share a video of himself last month with a sleeping 4-year-old boy. But the FBI had a new strategy. A foreign law enforcement officer got TeleGuard to hand over a small string of code the company had used to send push alerts - the pop-up notifications that announc