YELM, Wash. (AP) — Police say they're investigating reports that four students were groped while performing at a high school choir holiday concert.

KIRO reports that police in Yelm, Washington near the capital city of Olympia have been conducting interviews at the school since the incident happened at Yelm High School Wednesday.

The students said a classmate grabbed their buttocks while they were on stage for the evening performance in front of the full auditorium.

The suspected student hasn't been identified.

The father of one victim said his daughter was groped numerous times and that he wants to make sure it doesn't happen to other children.

Yelm police said the allegations are unusual but that they were taking it very seriously.