Long but tells the whole story:

In 1993, the US military was stunned when in it lost 18 elite soldiers in one day of fighting in the streets of Mogadishu.  After that incident, the military medical community realized they needed to make changes to the way they treated traumatic injuries sustained in combat.  From that, the Tactical Combat Casualty Care (TC3 or TCCC) was born.

The TC3 curriculum deviated greatly from the previously well-known A-B-Cs, or Airway Breathing Circulation, methods taught for generations in the military, and by extension law enforcement.  TC3 turned that practice on its head and began teaching the importance of tourniquets and wound packing.

In the early 2000s, ironically coinciding with the beginning of the Global War on Terrorism, the US Army implemented TC3 as the standard training curriculum for all of its new medics.  Greg Miller and Philip Belmont were among that first generation of Army medics to go through the transition.  They then took those new practices and lessons learned off to war; Phil on two deployments to Iraq with the 101st Airborne Division, and Greg to Afghanistan with the 173rd Airborne Brigade.

After nearly 3 and a half years of collective combat time, treating both American and Coalition soldiers, enemy combatants, as well as injured civilians, Phil and Greg returned home to begin careers in law enforcement. 

What they found was that while the US military was quick to embrace the changing medical practices, proven under fire, the American public, local law enforcement and Emergency Services resisted.  As late as 2010, the culture in many American police departments still very much relied on the A-B-C's, or Ambulance Before Cruiser methodology. However, a few progressive police departments began to push for change and train their officer in TC3.  Thankfully, Phil and Greg were members of one such department.

Once given the blessing of their command staff, Phil and Greg set out to create a comprehensive medical training program, specifically for police officers.  In doing so they collaborated with leading trauma physicians at some of America's, and perhaps the world's, leading hospitals (this is New England, after all).  In addition, they also reached out to former Army colleagues, to include US Army Special Forces and Special Operations medics, to ensure the curriculum was thorough, well rounded and based conclusive proof derived from the medical advancements expanded during the Global War on Terrorism.

Once the training program was in place, the results were immediate.  In less than 2 years, more than 15 police officers in their department were awarded Lifesaving Awards for having treated, and saved the lives of severely injured civilians. 

As knowledge of the police department's medical program began to spread many other agencies around the region came calling for help and training.  Realizing there was a tangible void in effective medical training available to police officers, the Tree Street Medical Group was born, and with it TSMG’s signature training course, Tree Street Medicine.