On December 13, 1990, Republic Act 6975 was signed entitled: “An Act Establishing the Philippine National Police under a reorganized Department of the Interior and Local Government, and for other purposes”. The passage of this law transpired the reorganization of the law enforcement agencies to which the former Philippine Constabulary and the Integrated National Police were merged serving as national in scope and civilian in character.
The reorganization gave birth to the creation of additional functional staffs of the PNP. On March 12, 1991, the Directorate for Investigation (DIN) was formally established. However, the officers and men of DIN did not stop on developing the Directorate which they anticipated the professionalization of the PNP as mandated by Republic Act 8551 signed on February 17, 1998. The DIN had passed a NAPOLCOM Resolution No. 97-032 entitled “Enhancing the Investigative Functions of the PNP through the Implementation of the Investigation and Detective Management Program”. The resolution also renamed DIN into Directorate for Investigation and Detective Management (DIDM) into which aside from its regular functions as mandated by law, the DIDM maintains a school, the PNP Detective School which offers regular courses on Criminal Investigation and Detective Development Course (CIDDC) and other crash courses on investigation. The professionalization of the PNP in the field of investigation was to keep pace with the sophistication of criminal offenders.
At present, DIDM has five (5) divisions namely, Research and Analysis Division, Case Monitoring Division, Women and Children Concern Division, Pre-Charge Investigation Division and Information Technology Division (interim).It also maintains special offices like the School for Investigation and Detective Development, National Crime Information System and National Task Force on Squatting and Squatters Syndicates.