Police Say Suspect Planned Colorado Shooting For Months

The tragic shooting that took the lives of 12 and injured nearly 60 people in Colorado during a late night showing of "Dark Knight Rises" was apparently planned for months.

According to the Associated Press, officials say that evidence shows the 24-year-old suspect James Holmes planned the attack with "calculation and deliberation."

Aurora Police Chief Dan Oates said the bright neurology student had a high volume of deliveries to his apartment and school at the University of Colorado Denver over the course of four months, including explosive materials and a high-capacity ammunition magazine. Holmes also purchased thousands rounds of ammunition on the web.

Police found his apartment rigged with jars of liquids, explosives and chemicals that were set to kill "whoever entered it," Oates said. By late Saturday afternoon, all hazards had been removed from the Holmes' apartment and residents in surrounding buildings were allowed to return home.

A federal law enforcement official also provided an updated account about the gunfire inside the Aurora theater, saying that the semi-automatic assault rifle the shooter used was jammed during the attack, forcing him to switch to one of many weapons he possessed in the shooting.

Holmes was held in solitary confinement for his protection at a Denver-area county detention facility, held without bond on suspicion of multiple counts of first-degree murder. He is set for an initial hearing on Monday and has been appointed a public defender.

President Barack Obama is scheduled to make an appearance in Colorado Sunday to visit with the families of the victims.