 Tumbelaka became commander of the battalion on 25 September 1950 when his commander, Maj. Abdullah, was killed during the military operation against the Republic of South Maluku.He later became part of the senior staff of VII/East Indonesia Military Territory or "Tentara dan Teritorium (TT) VII/Indonesia Timur".Tumbelaka's efforts to broker peace between the Indonesian government and the Permesta movement was formalized when he was appointed as deputy governor for North and Central Sulawesi on 23 March 1960.