It happened in front of a non-profit facility that helps people with disabilities.
Kaupas says a 20-year-old Joliet Township woman is in "very critical" condition after being shot several times. A man in his 20s was also shot and has been released from an area hospital.
Kaupas says the three were waiting outside Trinity Services in unincorporated Joliet Township to pick up the woman's sister from work when an unknown gunman approached and opened fire.
Witnesses say the man fled on foot after the shooting. No one else was injured. No arrests have been made.
The Associated Press contributed to this report.