An attempt by 2nd Lieut. Irving to confront Walker, resulted in the ex-Commandant drawing a sword against him. Eventually, Walker wandered off and was subsequently dismissed from the Native Police. He was later apprehended at Bromelton, charged with the embezzlement of £100 and sent to Sydney. By 1857, Walker was back on the northern frontier of British colonisation in Australia, employed on Serocold and Mackenzie's Cockatoo station. Here he formulated plans with squatter George Serocold to examine land for occupation in the upper reaches of the Comet River. He set out with another squatter named Wiggins and three Aboriginal men, two of whom were Peabody and Jamie Sandeman, to hunt for these pastoral runs. On returning to Cockatoo, Walker's camp was attacked by local Aboriginals at Conciliation Creek in the Zamia Valley. Walker received two severe spear wounds and with difficulty made his recovery at nearby Palm Tree Creek station owned by squatters Scott and Thompson. At this time the Hornet Bank massacre occurred and Andrew Scott requested assistance from the now recovered Walker to assist with the protection of his newly acquired land. Walker recruited ten of his ex-Native Police troopers and formed a private militia that roamed the Dawson River area conducting punitive missions against local Aboriginal groups. Walker utilised Hornet Bank station as a base and travelled as far as Mount Abundance during his patrols. His troopers included Larry, Boney, Jingle, Billy, Coreen Jemmy and Coreen Neddy. The troopers were actively recruited from the discharged members of the Native Police and were financed by local squatters unhappy with the government run force. George Serocold described the situation as a Border War and even called for the importation of the Cape Mounted Rifles from Africa to give a lesson to "these savages as will enable us to gain our moral ascendency, let them be made to feel the miseries of war". The Queensland Government eventually determined that Walker's private militia was illegal and ordered its dissolution in 1859. William Wiseman, the Commissioner for Crown Lands in the region, was sent to the Dawson River to enact the order. He found that Walker's troops were conveniently already dissolved and working on Andrew Scott's Hornet Bank and Pollet Cardew's Eurombah stations as shepherds earning £35 per annum. Frederick Walker was also employed as overseer and ex-Native Police officer Ross was superintendent. In September 1859, Walker officially became a pastoral squatter, taking up the Meteor Creek, Clematis, Carnarvon Creek and Consuelo runs in conjunction with established squatters Serocold, Wiggins and Mackenzie.