Proposed rules by the Obama administration to clamp down on the for-profit school sector may have been leaked in June a day before they were made public, a pair of Senators asking for a probe said on Thursday.

Gainful employment rules proposed by the U.S. Department of Education and set to take effect in 2012 are meant to restrict federal aid to schools which can ensure that students have a better chance of getting jobs after graduation.

The proposed rules, under embargo on June 15, were e-mailed by one of the non-federal parties involved in negotiating them, Senators Richard Burr R-NC and Tom Coburn R-OK said in a letter to the Department's Inspector General Kathleen Tighe. The rules were made public on June 16.

The Senators raised the possibility that groups who stand to benefit financially from the failure of the proprietary sector - which can includes publicly traded for-profit schools - may have received the document. Tighe's office is meant to act independently within the Department to ensure the integrity of its programs and operations.

Edie Irons, the communications director for non-profit education group The Institute for College Access and Success, e-mailed an embargoed copy of the program integrity regulations to the GainfulEmploymentGroup on June 15 at 5:38 p.m., the Senators noted, citing records released under a Florida public records request.

The Senators also cited a Freedom of information Act request was made on July 23 by political watchdog group Citizens for Responsibility and Ethics in Washington.

In that request the group sought information about contact between Department officials and individuals and organizations outside the Department. CREW said it wanted to inform the public about the extent to which the Department has knowingly relied on, or has been manipulated by, the views of individuals who seek to advance their financial interests in the for-profit industry by publicly criticizing certain for-profit education entities and companies.

Witnesses at congressional hearings over the past year have testified to Congress stating that the for-profit higher education industry has abused the federal student aid system to earn profits.