On 1 January 1919, the self-government based police became a national agency, subordinate to the Ministry of the Interior and led by the Police Directorate (). The Police Directorate was called "Politseivalitsus" between 1929-1938, and "Politseitalitus" between 1938-1940. On 17 December 1919, the Estonian Constituent Assembly passed the Police Act. A field police was established, which was tasked with protecting public safety and order. Police districts were formed based on counties and cities, these were divided into divisions, which were further divided into precincts. Criminal police was established on 5 January 1920, and the Estonian Internal Security Service on 12 April 1920. Furthermore, police reserve was established in 1920. The police consisted of field police and the Internal Security Service, which were subordinate to the Ministry of the Interior, and criminal police, which was subordinate to the Ministry of Justice. On 1 May 1924, the services were unified under the control of the Police Directorate. On 1 December 1924, there was a failed coup d'état attempt by the Soviets, in which five policemen were killed. This led to major revisions in the police force. The composition of staff was put in order, police reserves were enlarged, number of transportation vehicles was increased, more modern guns were taken into service and communication options were improved. In 1925, a police school was established in Tallinn.