SPARTA, Wis. -

The Sparta Police Department says it's investigating an alleged bullying incident that took place on a school bus on Tuesday, February 19.

School officials have already "taken some action" against one of the students involved in the incident, according to police.

Investigators have been interviewing students and have looked at surveillance video related to this case.

Sparta police and school leaders say several Facebook posts have surfaced, but they say "the validity of those Facebook postings is the responsibility of the poster and Facebook page administrator."

Police say more details will be released after their investigation is complete, which may be later this week.