Milwaukee Public SchoolsMILWAUKEE (CBS 58) -- The principal of Grantosa Drive School sent a letter to families notifying them that a paraprofessional is under investigation after allegedly hurting a student during bus pickup on Thursday, Sept. 18. In the letter to the school community, Principal Thaddeaus Hilliard said Milwaukee police went to the campus Friday and began a criminal investigation. Milwaukee Public Schools is also reviewing the matter. The staff member, a 63-year-old man, is not currently working at the school, according to the letter. Families were directed to contact the school office at (414) 393-4400 with questions.