WASHINGTON (Reuters) - A fire that gutted a U.S. Department of Agriculture (USDA) building in Maryland shows no initial signs of a crime being committed, a spokesman for federal investigators said on Wednesday.

The storage shed that burned on Tuesday was at a USDA complex in Beltsville, a Washington suburb, that was among department facilities in five states closed last week after anonymous threats were received.

"At this point in time it appears that no criminal act occurred," said Mark Cheplak, a spokesman for the Baltimore office of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

Cheplak said the agency made the announcement because of speculation about the fire after the threats. The ATF and the local fire department are investigating the cause of the blaze.

The shed was engulfed in flames and took about two hours to put out, a spokesman for the Prince George's County fire department said.

Scientists at the Beltsville site research poultry diseases, soybean genetics and genetic modification of animals used as food.

(Reporting by Ian Simpson in Washington; Editing by Jeffrey Benkoe)