Just moments after he shot dead 12 people and injured 58 others in the Aurora shooting massacre, suspect James Holmes seemed “very relaxed” and “detached,” a police officer testified Monday at a preliminary hearing. He originally thought Holmes was a fellow cop because of his calm demeanor and garb—layers of body armor, a helmet and a gas mask. Holmes, who was found standing outside his car in the cinema parking lot, did not exhibit “normal emotional responses to anything,” but eventually admitted that he had booby-trapped his apartment. Police were among the first to testify at the much anticipated, week-long preliminary hearing that began Monday. Prosecutors are expected to outline their case against Holmes—the first public disclosure of their evidence—and potentially the last we hear for months, as Holmes is still deemed mentally unfit for a criminal trial.