Sen. David Vitter said his Democratic counterpart on the Senate Environment and Public Works Committee has "completely relinquished" her Environmental Protection Agency "oversight obligations" by ignoring the John Beale scandal and attendant mismanagement at the powerful agency.

“The U.S. Senate, controlled by President Obama’s own party, refuses to conduct any meaningful oversight of the EPA, allowing the fraud and poor management to occur,” Vitter, R-La., said Wednesday morning. “A good — meaning bad — example of this enabling is that under the leadership of the Democratic chairman Barbara Boxer, the Senate EPW Committee has completely relinquished its EPA oversight obligations, failing to hold a single hearing on the Beale scandal. Thank goodness the U.S. House will take oversight action and shine a light on how the EPA’s mismanagement led to Beale’s theft and fraud.”

Beale was an EPA official who defrauded taxpayers out of almost $900,000 by skipping work under the pretense of being a spy for the Central Intelligence Agency.

Vitter's statement came as the House Oversight and Government Reform Committee held a hearing on accusations from the EPA's Office of inspector general that the agency was interfering with independent investigations into agency employees.

"Under the heavy cloak of ‘national security,' the Office of Homeland Security has repeatedly rebuffed and refused to cooperate with the OIG's ongoing requests for information or cooperation,” assistant EPA inspector general Patrick Sullivan said in his prepared testimony, obtained by the Associated Press. “This block unquestionably has hamstrung the Office of Inspector General's ability to carry out its statutory mandate to investigate wrongdoing of EPA employees.”

"It is extremely dysfunctional at the Office of Homeland Security," Sullivan added during the hearing.

Vitter and House Republicans are also continuing their own investigations of employee misconduct related to the Beale fraud, by questioning former EPA official Robert Brenner, the friend and colleague who hired Beale to the agency. Brenner is refusing to answer some questions.

“It is not the role of your paid counsel to determine the scope of a Congressional investigation,” wrote Vitter and House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif. "The joint investigation has only heightened the need for Congress to investigate your relationship with Beale and your actions at EPA. As such, if you continue to refuse to voluntarily cooperate with this investigation, OGR will be forced to consider the use of compulsory process to obtain this information."

The inspector general reported last month that another EPA official who was responsible for approving $184,000 in fraudulent time sheets and travel vouchers on Beale's behalf lied to investigators when asked why he received such lax treatment, according to a memo obtained by the Washington Examiner.