On 22 March 2005, he and other protesters publicly complained about police brutality while passively resisting arrest for obstructing a footpath, following a peace demonstration that went inside an ANZ bank. In May 2006 he filed papers at the Auckland district court seeking NZ$50,000 in damages from the New Zealand police after being pepper sprayed at a January 2005 protest against an alleged genetic engineering experiment outside the Forest Research Institute in Rotorua. On 2 July 2008, Judge Chris McGuire awarded Oosterman $5,000 damages and $25,000 court costs, saying police actions had not been reasonable, but rejected Oosterman's claim of assault saying the officer's actions did not quite meet the necessary "high threshold of blameworthiness".