Corderro Simpson and Bobbi Medina have both been charged with robbery.
Sioux City police say the man and woman walked the Save-A-Lot on Pierce Street and tried to steal beer.
The employee told police the two had stolen beer from them before, so they were watching them when they came in.
The employee said the two, again, tried to walk out with beer when employees stopped them, and a fight broke out.
During the fight, police say, the Simpson pulled out a knife and stabbed the employee several times.
The employee only suffered minor injuries.
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