John Larsen founded Larsen Forensics & Associates, Inc. in 2003 and serves as its President. In this capacity, Larsen has performed services for the U.S. Department of State as an Anti-Terrorism Advisor (ATA) related to the forensic processing of bombing crime scenes. He has also instructed the Chicago Police Department (CPD) and the West Suburban Violent Crimes Task Force in the development of their own Evidence Response Teams (ERTs). Larsen has significant experience as a testifying expert regarding the reconstruction of shooting incidents. For several years, Larsen served as an investigator for the Office of the Special Prosecutor of Cook County, and provided training for Sirchie Laboratories Inc. in the use of the Reflective Ultraviolet Imaging System (RUVIS).

John Louis Larsen, President

In 2008, Larsen started instructing law enforcement officers for the Suburban Law Enforcement Academy at the College of DuPage, Glen Ellyn, Illinois (current course listings available at He has been a licensed Private Detective in the State of Illinois since 2003.

From January 1981 to the end of June 2003 Larsen was a Special Agent for the Federal Bureau of Investigation (FBI). He was one of the founders of the FBI’s ERT program. Since 1984 he has been trained on the national and state levels as a Fire Investigator and served as the Arson Coordinator for the FBI Chicago Office from 1988 until his retirement. In his capacity as a Fire Investigator he has worked such major cases as MATCHBOX, the 1984 Casablanca Supermarket fire in Chicago, and the 2000 New Mexico Power Line Fire. As a case agent, Larsen investigated cases such as UNABOM and the Jeffrey Erickson escape attempt in which two federal officers were murdered. The Erickson case earned Larsen the U.S. Marshal’s Service award as the “Investigator of the Year” for 2002.

Throughout Larsen’s career in the FBI he worked civil rights, arson, and violent crime matters. His last duty assignment was to the Chicago Division where he was Senior ERT Leader. Other special assignments Larsen undertook while in the FBI included: the 1994 American Eagle Crash, the 1996 Summer Olympic Centennial Park bombing, the 1998 US Embassy Nairobi, Kenya bombing, and the 9/11/2001 United Airlines Flight 93 crash in Shanksville, Pennsylvania.

Larsen is also a certified police instructor. In this capacity he has taught courses at the FBI Academy in forensic processing, vehicle arson investigation, alternate light sources and crime scene interpretation. Larsen has instructed Chicago Police detectives and evidence technicians as a guest lecturer at the Chicago Police Academy, the South Bay Regional Public Safety Training Consortium in California, the Royal Omani Police and Omani State Security in Oman, the National Police and Army in Venezuela, and Ecuadorian National Police. He has taught forensic police schools throughout the United States, as well as three sessions at the International Law Enforcement Academy (ILEA) in Budapest, Hungary.