The Department of State has sent notice (which you can view below) to DefCad.org that their distribution of 3D printable weapons, and weapons parts, is in violation of the law.
The Office of Defense Trade Controls Compliance sent a letter to Cody Wilson, who runs Defense Distributed out of Austin, Texas, that he can not host and distribute his files until further review by the State Department.
Defense Distributed gave notice to followers via Twitter about the controversy:
#DEFCAD has gone dark at the request of the Department of Defense Trade Controls. Take it up with the Secretary of State.
— Defense Distributed (@DefDist) May 9, 2013
…This post will be updated as more details become available.