Republican Representative Kay Granger, who chairs the subcommittee, also sponsored the letter.

Barton, a Texas Republican, is co-sponsoring the bill with Illinois Democrat Bobby Rush, who chairs the subcommittee.

Levin, who chairs the subcommittee, directed many of his questions to Wibbelman and appeared frustrated at his testimony.

Wibbelman received the brunt of Levin's questions and the senator, who chairs the subcommittee, appeared frustrated at his testimony.

Senator Carl Levin, who chairs the subcommittee, said he had not yet decided whether to refer the report to criminal or civil authorities.

Lee, who chairs the subcommittee, has asked his staff to take a close look at the proposed deal, Conn Carroll, a spokesman for Lee, said.