It happened while the 13-year-old girl was walking to school near 59th and Wood.
Police say she was held at gunpoint and pulled into an alley where she was assaulted in the gangway between two vacant buildings.
Members of the Action Now organization say the incident could have been prevented.
They have been pushing for the Safe Passages ordinance which would require watchmen stationed at vacant buildings within 1,000 yards of a school.
