Cassie Tanner, a former legislative aide and one of five women who have publicly accused Democratic Rep. Steve Lebsock of sexual misconduct, announced Wednesday she has filed a formal sexual harassment complaint against the Thornton lawmaker.

Lebsock took to Twitter Wednesday afternoon to contend that House Majority Leader KC Becker had not received nor read any such complaint. However, Colorado Politics has confirmed a complaint was filed Wednesday.

“I had not filed a complaint until now because until yesterday I could not recall whether the harassment occurred in 2014 or 2015,” Tanner said in her letter. “Ironically, it was Rep. Lebsock himself who helped me determine which year the incident at 1Up occurred.”

Tanner pointed out that Lebsock had shared a picture on Twitter last week “in an effort to discredit me and paint me as a liar.” The picture showed Lebsock at 1UP in 2014.

@RepLebsock PACMAN 76,500. Challenge next wk@MediaMarcus @domoreno @RepNordberg @Singer4Colorado @JovanMelton pic.twitter.com/ReRizW0coX

— Steve Lebsock (@RepLebsock) March 28, 2014

Tanner said she looked for pictures of herself from the Young Democrats event in 2015. “I will never forget the shirt he unbuttoned that night so this picture confirms that it happened in 2015.” Tanner included a link to the photo from the Colorado Young Democrats’ Facebook page.

The event was reported in the media as having taken place in 2014, and Lebsock has used that to deny the sexual harassment claim, Tanner continued.

“I know what Rep. Lebsock did that night and so does he,” Tanner wrote. “This was also not the only incident of inappropriate sexual remarks or behavior directed at me by Steve. In another instance at an event he made lewd remarks about my breasts and the dress I was wearing. He was visibly drunk and I extricated myself from the situation as quickly as possible.”

Tanner said she intends to fully cooperate with the investigation. In addition to Tanner, former lobbyist Holly Tarry and Democratic Rep. Faith Winter of Westminster have also filed sexual harassment complaints against Lebsock.

Lebsock also told Colorado Politics Wednesday he is not sure he attended the 2015 Young Democrats event at 1Up. He pointed out in a recent YouTube video that he had publicly asked the accusers back in November to file formal complaints and that unless he resigns those working to smear him will “double down” and “triple down.”

Editor’s note: This story was updated Wednesday afternoon to reflect Lebsock’s assertion that Becker had not received a complaint as of Wednesday afternoon, as well as to confirm that a complaint had been filed. A complaint can be filed with one of several people in the House.