On Q Professional Investigations (ONQPI), a professional and experienced investigative services firm headquartered in Chicago, Illinois conducts a wide range of investigative services for corporations, law firms and private individuals – Locally, Nationally, Globally.

ONQPI Investigators have the experience, training and discretion to design and implement specialized detective services to meet your specific needs. ONQPI provides a vast number of investigative services and has successfully performed in-depth investigations on the following:

  • Accident
  • Accidental Deaths
  • Accounting Fraud
  • Adoption Tracing
  • Adultery Investigation
  • Alarm Systems
  • Arson
  • Asset Searches
  • Background Searches
  • Bank Fraud
  • Bodyguards
  • Burglar Alarms
  • Child Abductions
  • Child Custody
  • Child Kidnappings
  • Child Locators
  • Child Support
  • Child Welfare
  • Children’s Rights
  • Civil
  • Closed Circuit Television
  • Cold Case Homicides
  • Computer Crimes
  • Computer Forensics
  • Computer Fraud
  • Computer Security
  • Copyright/Trademark Infringement
  • Corporate Investigation
  • Corporate Security
  • Court Records Research
  • Criminal Defense
  • Criminal Prosecution
  • Crowd Management
  • Custody Services
  • Database Searches
  • Debugging
  • Decoy Services
  • Digital A/V Evidence
  • Digital Audio Evidence
  • Divorce Asset
  • Divorce Evidence
  • Domestic Investigation
  • Due Diligence
  • Electronic Surveillance/Countermeasures
  • Electronic Sweeps
  • Embezzlement
  • Event Planning/Safety
  • Event Security
  • Executive Protection
  • Expert Witnesses
  • Financial Fraud
  • Firearms
  • Forensic
  • Fraud
  • General Investigations
  • GPS Vehicle Tracking
  • Guard & Patrol Services
  • Heath Care Facility Deaths
  • Hidden Cameras
  • Home Security
  • Identity Theft
  • Industrial Accident
  • Industrial Espionage
  • Infidelity
  • Insurance Fraud
  • Interview and Interrogation
  • Loss Prevention
  • Missing Persons
  • People Searches
  • Polygraph Tests
  • Pre-Employment Screening
  • Pre-Tenancy Screening
  • Process Service
  • Records Research
  • Skip Tracing
  • Spousal Surveillance
  • Surveillance
  • Undercover
  • Video Depositions
  • Witness Locating
  • Workers’ Compensation