Sen. David Vitter, R-La., said today that former Environmental Protection Agency administrator Lisa Jackson used her “Richard Windsor” alias email account to pose as her own assistant when dealing with outside groups, adding that she also used the account to correspond with White House officials.

“EPA has shown an absolute disregard for transparency with their email practices, but this one is pretty bizarre,” Vitter said in a statement today. Vitter’s office released an email exchange between Jackson and Michael Martin, conducted from her Windsor email account, in which Martin clearly believes he’s dealing with an assistant named Richard Windsor, rather than the EPA chief herself.

“These emails demonstrate how the Administrator’s use of the Richard Windsor alias is unprecedented and nothing like the secondary email addresses used by previous EPA Administrators; none of which could be mistaken for a separate individual,” Vitter’s office said in the announcement.

Vitter also released emails showing that Jackson used the account to correspond with White House officials. “I have your special email from my friend Lisa H. — hope that’s okay!)” Cass Sunstein, then-White House Information and Regulatory Affairs administrator, wrote Jackson in 2009.

Jackson has previously denied doing anything wrong. “After 25 years in public service, I have people accusing me on both sides of doing something unethical to hide information,” Jackson said earlier this month, per The Daily Caller. “And I have endless times when I’ve said to people, ‘Make sure when you’re searching for FOIA information you search the Richard Windsor account.’”