MADISON, Wis. (AP) — 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.

The Wisconsin Democrat sent a letter to the Air Force office that handles congressional inquiries in mid-November asking it to investigate the claims involving members of the 115th Fighter Wing’s Security Forces Squadron, which polices the Truax Field Air National Guard Base in Madison.

Baldwin made the request after receiving a letter from Jay Ellis, a master sergeant in the security squadron. Ellis wrote that he learned of six incidents of sexual harassment or sexual assault against female members of the squadron that happened between 2002 and 2016, and that high-ranking officers have done little to address them.

A spokeswoman for the 115th Fighter Wing says the unit doesn’t tolerate such behavior and takes allegations seriously.