04/26/2011 05:59 pm ET Updated Jun 26, 2011

12-Year-Old Boy Shot Outside Of Chicago Elementary School

A 12-year-old boy is reportedly in serious condition after being shot in the back while leaving his South Side elementary school.

About 2:45 p.m., the boy was leaving Cook Elementary School in the 8100 block of South Bishop Street when he was wounded, the Chicago Sun-Times reports.

Police told the Chicago Tribune they believe the gunman is a former student who "approached a crowd of students and staff in front of the building and fired about four times" before fleeing the scene.

The seventh grader was taken to Advocate Christ Medical Center in serious condition, according to the Tribune.

Chicago Public Schools spokeswoman Monique Bond told NBC Chicago a motive in the incident was not yet known.