Washington, D.C. ? A Senate aide who handled Ted Stevens’ personal bills is cooperating with the Justice Department in a growing corruption probe into the Alaska senator’s dealings with a wealthy contractor.

Barbara Flanders, who serves as a financial clerk for Stevens, 83, on the Commerce Committee, testified under subpoena in the past several weeks and provided documents regarding the senator’s bills, according to an attorney in the case.

Investigators are scrutinizing Stevens’ relationship with oil field services contractor Bill Allen, who helped oversee a renovation project that more than doubled the size of Stevens’ Alaska home in 2000. Allen’s company, VECO Inc., won tens of millions of dollars in federal contracts. Allen has pleaded guilty to bribing Alaska lawmakers.