 The Australian Services Reconnaissance Department ( SRD ) also collected intelligence on Labuan and other parts of the Brunei Bay area during May . On the first of the month several RAAF PBY Catalina aircraft carrying SRD personnel overflew Labuan . These aircraft later landed near two native prahu and questioned their crews ; two sailors were flown back to an Allied base for further questioning . On 15 May two Malays working for the SRD were landed in Brunei Bay by a Catalina , and sailed to Labuan on board a prahu . These agents recruited a local civilian from Labuan , and the party was extracted by a Catalina near the mainland village of Kampong Mengalong on 19 May . The intelligence gained from these operations provided the Australians with a good understanding of Labuan 's geography and infrastructure . In addition , civilians who had been recruited by the SRD 's SEMUT 2 team ( which had been parachuted into Borneo during April ) provided intelligence on the size and movements of Labuan 's garrison force . 
