Another important reform introduced by the Military Government of occupation was the establishment of a professional, well trained and equipped armed force, supposedly “apolitical”. The entire military police system of the Dominican nation was dismantled, with the disappearance of the Republican National Guard, known as “La Guardia de Mon” and also the Municipal Police.
In place of the Municipal Police, the Constabulary, the Sixth Police System was created, whose organization corresponded to the North American model and its function was to maintain internal order and to enforce the executive orders of the North American government, its legal structure is based on North American executive orders.
The Executive Order of April 7, 1917 of the Military Government authorized the creation of the Dominican National Guard, under the command of officers of the infantry of the United States Navy. Its functions were similar to those of the Constabulary and it was also governed by U.S. executive orders, for the maintenance of public order and the security of the integrity of the state.
In 1921, during the administration of Rear Admiral Snowden, the National Guard changed its name to the National Police.
After the occupation forces left the Dominican territory in 1924, the Municipal Police resurfaced, distributed in 12 provinces, under the dependence of the town councils, under the President of the Republic and the immediate command of the Chief of Police, whose function was to maintain order and social stability in the country.
.On August 9, 1927, the Dominican National Police became the National Brigade and on May 17, 1928, the National Army. Trujillo was commander of the army until 1930. In that same year, the civic-military movement assaulted the San Luis Fortress, headquarters of the Northern Department of the National Army. It extended to Santo Domingo, forcing the resignation of President Horacio Vásquez, by order of the Chief of the National Army, who was the head of the movement. The Municipal Police was dismantled in Santiago, Dajabón, Moca and Santo Domingo, for being against the coup d'état of February 23. The National Congress on November 5, 1930, by means of Law 14, granted the Executive Power the power to appoint, dismiss and transfer the municipal commissioners.
The Dominican National Police was created in 1936, by Decree No. 1523 of March 2, as a body with national jurisdiction, with the mission of maintaining order, public tranquility, the security of persons and property, the prevention of infractions, the pursuit and apprehension of criminals and their submission to the action of justice. Trujillo wanted a police order that would respond to his excessive desire to perpetuate himself in power.
He knew that the Municipal Police System did not guarantee him control, he did not enjoy the sympathy of some members of that police force, the decision to group all the municipal police forces into a single entity with the name of “National Police” guaranteed him the desired control. The first chief of the National Police was Colonel Miguel A. Román Hijo.