According to a report, which contains new details of the Aurora theater shooting, the responding officer initially believed suspect James Holmes was a fellow officer because he noted that Holmes was wearing body armor. The officer ultimately realized his mistake when he noticed Holmes was walking away from the theater, not toward it as other officers were doing.
Specific details of the shooting have been limited over the past six months, stemming from a judge's gag order. However, because Holmes' trial began its preliminary phase this week, that information can be released to the public.
Also detailed in the new report, authorities say Holmes seemed detached upon his arrest, and that he voluntarily told officers that his apartment was rigged with a bomb.
Holmes is accused in the July 20 attack, when officials say he walked into a midnight screening of "The Dark Knight Rises," tossed two gas canisters into the crowd and opened fire. The attack left 12 people dead and dozens more injured. At the time of the attack, witnesses said Holmes appeared to be dressed up as "The Joker" -- the primary villain in the Batman series.
Officials say Holmes has a history of severe mental difficulties and had seen several psychiatrists. Prior to the shooting, Holmes purchased two Glock semi-automatic handguns, a pump-action shotgun and a semi-automatic assault rifle. Additionally, he purchased more than 6,000 rounds of ammunition for the firearms on the Internet.
Holmes, a former graduate student at the University of Colorado Anschutz Medical Campus, had been perceived as a near "straight-A" student in college -- carrying a GPA of 3.949 -- and was noted by school administrators as an "effective leader." Although a comprehensive motive for the attack is unknown, authorities believe that Holmes' recent academic struggles may have played a role. In early 2012, Holmes performed poorly on at least two exams and his academic standing was in decline.
Holmes has been charged with 12 counts of murder and a variety of other offenses. His preliminary trial is expected to last the rest of the week.