A woman in her 30s is under investigation Thursday for stabbing a skating coach she accused of rape when she was still in high school.

The suspect attacked the coach, who is in his 40s, with a knife at 7:25 p.m. Tuesday at the Taereung International Ice Rink in Nowon-gu, northern Seoul, inflicting injuries on the face and hand, according to the Nowon Police Station.

The suspect told police that the attack was motivated by her discontent over the authorities’ handling of a case she filed against the victim more than 10 years ago, accusing him of raping her when he was her coach and she was a high school student. The coach was refferred to the prosecution for charges including rape and aggravated assault, but the rape charge was dropped due to insufficient evidence.

The prosecution issued him a summary fine of 3 million won ($2,170) for the assault charge in 2016.