MADISON, Wis. — U.S. Air Force investigators have confirmed they’re looking into allegations of sexual assault and harassment within a Wisconsin Air National Guard security unit, U.S. Sen. Tammy Baldwin’s office said Wednesday.

Baldwin, a Wisconsin Democrat, asked the Air Force on Nov. 13 to investigate claims involving members of the 115th Fighter Wing's Security Forces Squadron, a group of about 100 airmen that polices the Truax Field Air National Guard Base in Madison.

Senator seeks Wisconsin Air National Guard sexual misconduct probe Sen. Tammy Baldwin has asked Air Force investigators to look into allegations of sexual assault and harassment within a Wisconsin Air National Guard unit that were brushed aside by senior officers, according to a member of the unit.

Baldwin made the request after Jay Ellis, a master sergeant in the squadron, contacted her office and said he had learned of six incidents of sexual harassment or sexual assault against female squadron members between 2002 and 2016. He alleged that high-ranking commanders have done little to address them. One of the women told The Associated Press in an interview that superior officers sexually assaulted her and her friend during a party in 2002 at a training base in Nevada as the unit was preparing to deploy to Iraq.

None of the women in any of the incidents Ellis cited filed formal complaints out of fear of retaliation, Ellis said.

Members of the 115th Fighter Wing attend a departure ceremony at Truax Field in Madison, Wis., Aug 3, 2017. (Master Sgt. Paul Gorman/Air National Guard)

The Air Force Office of Special Investigations wrote back to Baldwin on Nov. 16 saying the matter had been referred to personnel responsible for the Madison area. The letter did not say if an investigation was underway.

Ellis told the AP that investigators from Scott Air Force Base in Illinois contacted him on Nov. 16 and asked him for details of the incidents and the names of the people involved.

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Baldwin's office on Wednesday released a letter from the AFOSI dated Dec. 21. AFOSI Inspector General Jacqueline Albright wrote in the letter that investigators spoke with Ellis on Nov. 16 but he wouldn't identify any of the victims. He called back on Nov. 28, however, and provided one woman's name. Albright said the AFOSI is conducting a complete review of all the information Ellis provided in the two conversations and "has initiated additional investigative steps" based on his information.

Baldwin spokesman John Kraus said her office received the letter this week but it wasn’t processed until Wednesday.