Federal authorities have arrested a man in Logan, Utah, suspected of mailing of threatening letters addressed to the Pentagon and the White House, some of which initially tested positive for the poison Ricin. Subsequent tests determined the mailings contained a castor bean substance, an ingredient used to manufacture Ricin, according to two federal officials.
William Clyde Allen III, a Navy veteran, was taken into custody in Utah on Wednesday, two days after the packages and letters were discovered at mailing facilities. The U.S. Attorney's Office in Salt Lake City said federal charges were expected to be filed Friday.
Allen served in the Navy for four years, leaving the service in 2002. The motive remains under investigation.
The FBI said Wednesday that agents and law enforcement partners conducted an operation in Utah and potentially hazardous chemicals were involved. Individuals were asked to stay away from the area, but the Logan City Police Department said there was "no wider threat to public safety at this time."
None of the threatening mailings reached the Pentagon or White House.
The Associated Press contributed to this report.