(CBS/AP) CENTENNIAL, Colo. - Police officers who arrested James Holmes after the Colorado movie theater massacre testified Monday that the suspected gunman, clad in body armor, as unusually relaxed but fidgety at times.
At a preliminary hearing, Officer Jason Oviatt said Holmes seemed "very, very relaxed" and didn't seem to have "normal emotional reactions" to things.
"He seemed very detached from it all," Oviatt said.
The hearing is the first extensive public disclosure of the evidence against Holmes.
Holmes didn't resist arrest behind the theater and volunteered that his apartment had been booby trapped, the officers testified during the opening of a hearing in which prosecutors began laying out their case against the former neuroscience graduate student.
When Oviatt first saw Holmes in his gear standing next to his car behind the theater, he thought he was a fellow officer but then realized Holmes was standing still, and not rushing toward the theater.
Oviatt pointed his gun at him, handcuffed him and searched him. He said he found two knives and a semi-automatic handgun on top of Holmes' car. Oviatt said an ammunition round also fell out of Holmes' pocket and he found another one on the ground.
Officer Aaron Blue said Holmes was fidgeting around after he and Oviatt put him in a patrol car, prompting them to stop and search Holmes again. They were worried they might have missed something because of Holmes' bulky outfit.
Investigators say Holmes tossed two gas canisters and then opened fire during the midnight showing of the Batman movie "The Dark Knight Rises" on July 20, killing 12 people and wounding dozens.
The preliminary hearing is expected to last all week. It will allow the judge to determine whether the prosecution's case is strong enough to warrant a trial but it's rare for a judge not to order a trial if a case gets this far.
Holmes is charged with more than 160 counts, including murder and attempted murder.
Legal analysts say that evidence appears to be so strong that Holmes may well accept a plea agreement before trial.
In such cases, the preliminary hearing can set the stage for a deal by letting each side assess the other's strengths and weaknesses, said Laurie Levenson, a former federal prosecutor and now a professor at Loyola Law School in Los Angeles.
At this stage, prosecutors must only meet a "probable cause" standard - much lower than the "beyond a reasonable doubt" standard for a guilty verdict, said Mimi Wesson, a professor of law at the University of Colorado Law School.
Many of the survivors and family members of the dead attended the hearing.