Illinois All-Party

Licensing & Regulation

Illinois licenses PIs through the Illinois Department of Financial and Professional Regulation (IDFPR) under the Private Detective, Private Alarm, Private Security, Fingerprint Vendor, and Locksmith Act of 2004 (225 ILCS 447). Applicants must be 21+, demonstrate three years of investigative experience or equivalent education, pass a written examination, submit fingerprints, and pay licensing fees. Illinois maintains some reciprocity. Renewal is triennial.

Physical Surveillance

Public surveillance is permitted. Illinois has the Freedom from Drone Surveillance Act (725 ILCS 167) that constrains law-enforcement drone use; private use is governed by FAA Part 107. GPS tracking on a non-owned vehicle is criminal stalking under 720 ILCS 5/12-7.3.

Audio & Video Recording Consent

Illinois is one of the strictest eavesdropping states. The Illinois Eavesdropping Statute, 720 ILCS 5/14-1 et seq., was struck down in part in People v. Clark and People v. Melongo (2014) for being unconstitutionally overbroad. The legislature responded in late 2014 with a revised statute that requires all-party consent for "private" conversations — those where at least one party has a reasonable expectation of privacy. The revised statute carries penalties up to a Class 4 felony for surreptitious recording of a private conversation. Recording in genuinely public spaces, or where no party has an expectation of privacy, is generally permitted. The safe assumption for PIs is to obtain all-party consent for any audio recording.

Domestic, Marital & Infidelity Investigations

Illinois is a no-fault divorce state since 2016 (irreconcilable differences only). Marital misconduct generally does not affect property division but can affect maintenance in cases of dissipation. PIs do extensive matrimonial work but must scrupulously observe the all-party consent rule when audio is involved.

Cybersecurity, Hacking & Digital Investigations

720 ILCS 5/17-50 and 17-51 (computer fraud and computer tampering) are broad. Illinois's Biometric Information Privacy Act (BIPA, 740 ILCS 14) imposes significant constraints on biometric data collection and has been the source of major plaintiff verdicts. OSINT is permitted; pretexting is barred federally.

Missing Persons, Skip Tracing & Harassment

Illinois State Police coordinate missing-persons cases. DPPA fully applies. The Illinois stalking statute (720 ILCS 5/12-7.3) is broad and includes electronic and surveillance conduct.