MINNEAPOLIS (AP) — A judge has found a Minnesota substitute teacher guilty of mistreating students at an elementary school.

Sixty-year-old Laura Avery was found guilty Monday of four charges of malicious punishment of a child. She was acquitted on a charge of tampering with a witness.

Authorities say Avery kicked a fifth-grade student in the shin and slapped another in the face while she was working at Oak Grove Elementary in Bloomington.

According to the charges, a school employee found four students crying in the hallway on Dec. 13, 2012. The students said Avery swore at them and threatened to slap them if they didn't do what she asked.

Bloomington school officials say they removed Avery from the classroom as soon as they became aware of the incident.