A convicted sex offender was charged with walking up to children outside a school in the Clearing neighborhood on the Southwest Side Thursday.

Karl Trujillo, 39, was approaching children outside a school in the 6300 block of South New England about 3 p.m. Wednesday, according to a statement from Chicago Police. A school administrator saw Trujillo and alerted police after learning Trujillo had no children at the school, police said.

When police arrived, Trujillo began running, but was arrested after a brief foot pursuit, police said.

Trujillo was convicted of aggravated sexual abuse against a 15-year-old in Will County, according to the Illinois State Police sex offender registry.

Trujillo, of the 7300 block of West Archer Avenue in Summit, was charged with one felony count of entering a school zone as a sex offender, one misdemeanor count of reckless conduct and one count of resisting police, the statement said.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2014. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)