John Allen Muhammad born John Allen Williams changed his name and joined the Nation of Islam.  Muhammad along with his co-defendant Lee Boyd Malvo carried out what became known as the 'Beltway Sniper Attacks'.  Muhammad was sentenced to death and executed on November 10, 2009. 

One page handwritten letter signed, "Muhammad". 
Includes the prison mailed envelope which he has drawn lines on the back and written 'look'.