It seems that she filed tax returns (twice) with a man she wasn't married too.
http://tennesseestar.com/2019/06/07/an-minnesota-investigation-finds-rep-ilhan-omar-violated-the-states-campaign-finance-laws/
Tax fraud. She filed with Ahmed Hirse while married to Ahmed Nur Said Elmi .
She also committed campaign fraud.
Cue up the usual muslim excuse making.