MILWAUKEE -

Members of Congress are calling for an investigation into the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives following a Milwaukee Journal Sentinel report that the agency conducted a flawed sting operation in Milwaukee.

The newspaper reported Wednesday that the ATF ran a 10-month storefront operation intended to bust felons for drug and gun offenses. But no major drug dealers or gang members were taken down. Also, the store was robbed of $35,000 in merchandise, and agents left behind a document listing undercover agents.

On Thursday the newspaper reported that Republican and Democratic members of Congress want more details.

Republican U.S. Sen. Chuck Grassley of Iowa said he'll be asking the ATF questions.

Republican U.S. Rep. Jim Sensenbrenner of Wisconsin said Wisconsinites deserve answers, and he'll demand them.