G.D. Investigations was officially established in 2007. However, the spirit of the agency was born back in 1997 when Kevin Gannon promised the parents of a victim of a mysterious drowning in Manhattan that the perpetrator(s) would be caught. The team's investigative strength grew with the addition of Anthony Duarte & Mike Donovan in 2005. Technical expertise in the areas of crime mapping and criminology were added in 2006 when D. Lee Gilbertson joined the team.
In 2014, the teams first book was published titled Case Studies in Drowning Forensics. When a corpse is found in a body of water, authorities generally presume that the manner of death was either an accident or a suicide. They do not treat the recovery site as a potential crime scene or homicide, so many cases remain unsolved. Case Studies in Drowning Forensics investigates the cases of 13 bodies recovered from water in similar circumstances and one survivor. The product of intensive field investigation and archival research, this is the first book that presents and explains forensic autopsy evidence associated with the "Smiley Face" murders.