In screenshots from a new video purportedly released by the Islamic State titled "My Father Told Me," ISIS child soldiers mass execute bound captives in a training exercise. Later, a man is thrown off a roof to his death. The video was released on ISIS terrorist channels on December 29 after a trailer teasing its release was shared earlier in the morning.Heavy is an independent news organization. We report acts of terror and violence so that the public may be fully informed. This may include content considered graphic, which is identified. We do not support, in any way, the individuals or organizations involved.