CHICAGO (CBS) — A 4-year-old girl was sexually abused inside a Northwest Side elementary school, according to police.

Investigators said it happened on the morning of Monday, Sept. 16, at Frank W. Reilly Elementary School, located at 3650 W. School St. in the Avondale neighborhood.

Police said the girl was inappropriately touched by a man inside the girls’ restroom.

Police were still investigating Sunday night.