FBI agents and Detroit police officers conducted an operation to serve arrest warrants against 11 men on Oct. 28 who had been charged with several federal crimes, including theft from interstate shipments, mail fraud to obtain the proceeds of arson, illegal possession and sale of firearms, and tampering with motor vehicle identification numbers. The 11 men were members of a group that calls itself "The Ummah" (Arabic for nation or community of believers), which is largely comprised of African-Americans who converted to Islam (many of them while in prison). The Ummah is headed by Jamil Abdullah Al-Amin, formerly known as H. Rapp Brown, who is serving a life sentence at the federal Supermax facility in Florence, Colo., for the murder of a police officer in Georgia.