More than 18,000 people have died in Nigeria's seven year conflict with Boko Haram, the terror group known for abducting hundreds of Chibok schoolgirls. A Boko Haram trademark has been its stealth. VOA has obtained a trove of secret videos made by Boko Haramvideos that show firsthand the atrocities committed against defenseless Nigerians at the height of Boko Haram's control of northeast Nigeria; executions, beatings and rule by fear