OKLAHOMA CITY (AP) — A Democratic member of the U.S. Senate committee that conducted confirmation hearings for Environmental Protection Agency Administrator Scott Pruitt said in a letter Tuesday that Oklahoma's former attorney general presented "inconsistent and contradictory statements" to the panel.

Pruitt's "misleading answers, evasiveness, and stonewalling" had stymied the committee's ability to provide oversight of the agency, Sen. Sheldon Whitehouse of Rhode Island wrote in a letter containing information about an ethics complaint against Pruitt being investigated by the Oklahoma Bar Association.

"This conduct is unbecoming of an attorney who is also a public official and who, under law, is required to testify truthfully to Congress," Whitehouse said.

The complaint was filed against Pruitt in March by the Center for Biological Diversity, a nonprofit organization that works to protect endangered species, and associate professor Kristen van de Biezenbos of the University of Oklahoma College of Law. Whitehouse is listed as a witness on the complaint.

The complaint says Pruitt may have violated the Oklahoma Rules of Professional Conduct when he told the Senate committee in January that he only used his attorney general's email address to conduct official business.

But documents released by the Oklahoma Attorney General's Office through an Open Records Act lawsuit in Oklahoma indicate Pruitt also used a personal email address to conduct official business, seeming to contradict Pruitt's sworn testimony, according to the complaint.

Personal emails and other documents indicate Pruitt coordinated closely with fossil-fuel companies and special interest groups who worked to undermine federal efforts to curb planet-warming carbon emissions while serving as the state's attorney general.

Democrats on the Senate panel have criticized Pruitt's close ties to the oil and gas industry. As Oklahoma's attorney general, Pruitt frequently sued the agency he now leads, including filing a multistate lawsuit against the EPA opposing the Obama administration's plan to limit carbon emissions from coal-fired power plants.

In April, Whitehouse accused Pruitt of violating federal law by agreeing to be the keynote speaker at the Oklahoma Republican Party's annual gala dinner. Whitehouse filed an ethics complaint claiming that would violate the Hatch Act, which limits the political activities of executive branch employees.

"You do not want to miss Pruitt at this year's OKGOP Gala, as he discusses his plans to slash regulations, bring back jobs to Oklahoma, and decrease the size of EPA!" said a flyer for the event sent out by the state party. Pruitt later withdrew from the event.

Gina Hendryx, the bar association's general counsel, didn't immediately return a telephone call from The Associated Press seeking comment.

Neither Pruitt nor the EPA immediately responded to an email requesting comment.