back to his homeland of kuwait but reportedly was prevented from doing so by authorities. according to the bbc, he came to the attention of counterterrorism officials in britain, as thought to be involved with extremists over in africa. while he made he way to syria and joined isis he guarded western hostages. three were dubbed the beatles because of their accents, and according to all reports, they were brutal. quote -- they were really one of had the hostages. when was the beatles show up there was some physical beating or tower further. they seemed to take pleasure. the abuse included prolonged beatings, mock executions and repeated waterboarding. for more on the i haddentity of this brutal man, i'm joined by richard engel. what do we know about mohammed emwazi emwazi. >> reporter: you outlined his biography.