The Parliament enacted the Essential Supplies and Services Act, 1947 according to the “Sorrento Villa Plan”. The Ministry of Commerce and Supplies issued an Order to prevent losses of public Supplies under section 3 of that Act. The Civil Supplies Theft Prevention Committee was formed and it was led by the Secretary of the Ministry of Commerce and Supplies and 2 members. The duties of the Committee are to prevent the losses of public supplies and to conduct investigation. Subordinate to that Committee, the Project Investigation Squad was formed. It was led by a District Superintendent of police from the Criminal Investigation Department, Insein, with other 15 police officers as members.

In 1948, the Civil Supplies Theft Prevention Committee was renamed as Public Property Protection Committee and so also was the Project Investigation Squad as Public Property Protection Police. Its strength was reinforced up to 30 members and led by District Superintendent of Police. In 1950, the Public Property Protection Committee was transferred to and became under the control of the Ministry of Home and Religious Affairs.

On 1ˢᵗ September 1951, by the Order No. 142 H. C 51 of the Ministry of Home and Religious Affairs, the Bureau of Special Investigation was founded for the first time as a separate organization. In October 1951, the Special Investigation Administration Board and Bureau of Special Investigation Act, 1951 was promulgated and accordingly, the Public Property Protection Committee was renamed as Special Investigation Administration Board, also reinstituted with one Chairman and 4 members. The Bureau of Special Investigation was constituted under section 2 of the said Act, and at that moment, its strength was 20 gazetted officers, 227 non-gazetted officers and 68 staffs, totally 315. Since then, media became to call the Bureau as “Sa-Thone-Lone” in Myanmar word and as “BSI” in English, for its respective acronym term.