A Minnesota Senate staff member filed a complaint with the Senate's human resources department on Tuesday charging that state Sen. Dan Schoen, DFL-South St. Paul Park, sent her a photo of a man's genitals in 2015.

Ellen Anderson told Minnesota Public Radio that Schoen used Snapchat, a mobile messaging app, to send her the sexually explicit photo.

Schoen was a House legislator at that time but was elected to the Minnesota Senate in 2016.

Schoen's attorney, Paul Rogesheske, denied that his client sent such a sexual message to Anderson or any other woman.

Schoen is accused of having made unwanted advances toward women and groping a woman from behind. He told the online news outlet MinnPost that the allegations were taken out of context or, in some cases, are false.

Several political leaders, including Gov. Mark Dayton, have called on Schoen to resign, but Schoen has continued to say he did nothing wrong. He has hired a lawyer and is preparing to fight, according to officials.

A friend of Anderson said she was present when the message came through. Lyssa Leitner, who works for Washington County, told MPR: "I said, 'Were you expecting that? Had that happened before?' She said, 'Nope, that was unexpected. Clearly I do remember her yelping in an 'oh my gosh' type moment."