The Japanese dismantled much of the island's colonial infrastructure and chose to support nationalist movements which would oppose the return of Dutch authorities.
[3] With the world war II over, the Dutch government sought to regain control over its former colony in Indonesia, which had declared itself independent from the Netherlands on 17 August 1945.
On 26 October, British soldiers and men from the Netherlands Indies Civil Administration landed in Surabaya to occupy the city, which had recently been evacuated by the Japanese garrison.
Violence soon began, and soon former members of PETA, including Mangundiprojo, formed units to fight against the British forces.
However, the situation escalated when Mangundiprojo was captured by the Anglo-Indian soldiers, and in the confusion, Mallaby was killed by members of the crowd while the brigadier sheltered in his car.
During the later Indonesian war of Independence, Mangundiprojo played a role in seizing a large sum of money that the Dutch colonial authorities were keeping in a bank.