50 ILCS 705/10.2: Criminal background investigations.

(a) On and after March 14, 2002 (the effective date of Public Act 92-533), an applicant for employment as a peace officer, or for annual certification as a retired law enforcement officer qualified under federal law to carry a concealed weapon, shall authorize an investigation to determine if the applicant has been convicted of any criminal offense that disqualifies the person as a peace officer.

(b) No law enforcement agency may knowingly employ a person, or certify a retired law enforcement officer qualified under federal law to carry a concealed weapon, unless (i) a criminal background investigation of that person has been completed and (ii) that investigation reveals no convictions of or pleas of guilty to offenses specified in subsection (a) of Section 6.1 of this Act.