An American fugitive, Mohamed Abdullahi Hassan, known online as “Miski,” who officials say is suspected of recruiting impressionable young men for terrorist groups including ISIS and was linked to at least one domestic terror attack in the U.S., has turned himself in to authorities, the State Department announced today. His influence is quite extensive," David Ibsen, Executive Director of the Counter Extremism Project, told ABC News after the Garland attack. "He's known as one of the go-to individuals online who individuals who want more information about how to travel to ISIS-controlled territory, who want information about what these radical groups are doing, they go to him."