On 03 June 1971, Headquarters Philippine Constabulary, Camp Crame issued General Orders Nr 224 activating IV PC Zone effective as of 16 May 1971 with its base in Camp Parang (presently SK Pendatun) to oversee all Constabulary units in Mindanao. Shortly thereafter, HPC issued General Orders 77 dated 01 August 1978 deactivating the IV PC Zone and activated the PC/INP Regional Command 12 to conform with the Local Government regionalization structures. It covers the so called “Cotabato Empire” which was subdivided into four (4) provinces namely: North Cotabato, Sultan Kudarat, Maguindanao and South Cotabato. Likewise, PC/INP of RECOM 9 was realigned to cover the provinces of Lanao Norte and Lanao del Sur including the cities of Iligan and Marawi.
Upon the creation of Autonomous Region in Muslim Mindanao, RECOM ARMM was created pursuant to HPC/INP General Orders Nr 56 dated 18 January 1991. RECOM ARMM took over Camp Parang as its Regional Headquarters, while the seat of RECOM 12 Headquarters was transferred to Isulan, Sultan Kudarat which is co-located with Sultan Kudarat Provincial Command. It comprises the Provinces of Cotabato, Sultan Kudarat, South Cotabato, Sarangani and the two cities of Cotabato and General Santos.
On 10 November 1993, PNP Regional Command 12 was officially named Camp Col Amando M Dumlao Sr pursuant to HPNP General Orders Nr 862 and was inaugurated by President Fidel V Ramos on 15 December 1993.
On 01 April 2000, PRO XII office transferred to its new site of office to Tambler, General Santos City while an Advance Command Post is co-located with General Santos City Police Office at Camp Fermin Lira, General Santos City.