An experimental-simulation approach was utilised in order to examine decisions made by investigators in the controversial Australian counter-terrorism operation concerning Dr Mohamed Haneef. The police were criticised by the media and contemporary commentators in regards to their handling of this operation due to the perception that they had made poor decisions and thus demonstrated bias against an innocent individual. To determine the quality of these critical investigative decisions, 81 participants were presented with a simulated counter-terrorism vignette based on a de-identified version of the Haneef case. Participants were required to make judgements concerning whether a suspect, whose cousin was the instigator of a terrorist attack, was involved in and/or aware of this attack. The vignette was manipulated so that guilt-suggestive information was presented either early or late and so that the suspect was either cooperative or uncooperative throughout an interview with a police officer. This was in order to model the influence of confirmation bias and co-operation, respectively. Overall, participants judged the fictional terrorist suspect to be reasonably guilty of supplying material support to a terrorist organisation, of having prior knowledge of the terrorist organisation, and of having a medium level of risk of potential future involvement in terrorism. Participants judged the suspect to be slightly but significantly lower on these criteria if he was cooperative throughout the police interview.