Polisi Istimewa or Special Police role in defensing Indonesian battle is very significant. In Japanese occupation, this unit was named as ‘Tokubetsu Keisatsu Tai’, a battle-trained troop. Japanese also formed Heiho, a troop which is separated from Japanese military unit, PETA (Pembela Tanah Air).
After proclamation by Ir Soekarno and Moh Hatta in 17 August 1945 and Surabaya people did not hear this directly. Japanese was tricky that it dismissed Haidan PETA in Gunungsari Surabaya and Heiho without giving information about Japanese loss in East Asia. In 19 August 1945, Surabaya people knew about Independence proclamation from Soeara Asia news paper.
One of high quality of troop and had arms in Surabaya was Polisi Istimewa led by Mon Jasin, yet there was a possibility that Japanese would disarm Polisi Istimewa.
Former Daindancho Gresik, drg Moestopo ordered former Shodancho Abdurahman to meet head of Polisi Istimewa Moh Jasin to warn him tot to be alert of Japanese to disarm his squadron. On Tuesday 21 August 1945, at 07.00, all Polisi Istimewa squadron, round 250 members, gathered in front of Polisi Istimewa base, on Jalan Coen Boulevard, Surabaya, currently Jalan Polisi Istimewa. After raising The Red and White, Inspector Moh Jasin read proclamation: “Oentoek bersatoe dengan rakjat dalam perdjoeangan mempertahankan Proklamasi 17 Agustus 1945, dengan ini menjatakan Polisi sebagai Polisi Republik Indonesia.” (To unite with people in stuggle to defense 17 August 1945 proclamation, with this stated that police as Republic Indonesia Police’
After reading proclamation,Jasin asked all police members to do parade alert to show force and battle preparedness. With steel vehicle and trucks with red and white flag heading to Jalan Tunjungan, Surabaya. Proclamation then typed and spread and attached on street. Proclamation supported former Heiho troop and PETA which had been dismissed to take over and disarm the Japanese.
Police of Republik Indonesia was involved in the effort to attack and take over Japanese arms. In Kempetai building raid, as Japanese fortress defense, Jasin had discussion with Kempetai commander. If Kempetai gave up then he would guarantee their lives. The freedom fighters then took the Japs weapon stored in their arsenals. They also raid Japanese Navy arsenal in Embong Wungu street that ended by surrendering arms and signed by Jasin as the Indonesia representative. The arms handover at Don Bosco building at Jalan Tidar, the biggest Japanese arsenal in South East Asia, Yasin waas assisted by Bung Tomo. Surabaya was then under the surveillance of Police of Republic Indonesia.
With the arms, Moh Jasin the led his troop directly to face British and Dutch landed in Tanjung Perak harbor of Surabaya on October 25 1945. Polisi Republik Indonesia was also involved in flag incident at Hotel Yamato and 10th November 1945 battle in Surabaya. The Polisi Republik Indonesia troop showed its force and showed never-give-up attitude. Jasin ordered his troop to attack and protect Indonesian organization which moved backward to the city fringe. He applied guerrilla strategy.
On 14 November 1946, Prime Minister Sutan Sjahrir changed Polisi Istimewa to Mobile Brigade (Mobrig) and later the term changed to Brigade Mobil (Brimob) on 1961. The date then decided as the anniversary of blue beret , the alias of Brimob. Moh Jasin was born in Bau bau, Buton on 9 June 1920, formed Brimob as ordered by the head of Republic Indonesia Police, Raden Said Soekanto Tjokrodimodjo, when he was the head of Malang Police. Jasin then was promoted as the father of Indonesia Police Brimob.