( CNN ) -- Colorado theater shooting suspect James Holmes will wear a hidden harness under his clothes to restrain him during his trial , which will have the largest jury pool in state history . Holmes is accused of killing 12 people and wounding dozens more in an Aurora movie theater . He will wear the harness , which will be anchored to the floor , because of the violent nature of his alleged crimes , a judge said . Judge Carlos Samour Jr. will send out 5,000 jury summons and expects at least 3,200 people will end up in court , he ruled on Thursday . That would mean each of the 450,000 Arapahoe County residents eligible for jury duty would have a 1 in 90 chance of being called , for this one case alone , court spokesman Rob McCallum told CNN . The idea is to bring in 800 prospective jurors at a time on Thursdays and Fridays early next year , a process that McCallum says could take three to four weeks . Those thousands will be winnowed down to 12 men and women for the start of the trial , which is set to begin February 3 . It is expected to last four months . Judge accepts theater shooting suspect 's insanity plea . Asking more people than usual to come to court for high-profile cases is common in the U.S. justice system , given concerns many of them already know the story and have strong opinions about it . In Florida , for example , there was a 500-person jury pool for the now-ongoing murder trial of George Zimmerman , who is accused in the killing of teenager Trayvon Martin -- a case that drew national headlines for weeks . So too , of course , did what happened just after midnight the night of July 20 , 2012 , in the Denver suburb of Aurora . It was then and there , authorities say , that a man walked through an exit door into a crowded Theater 9 of the Century movie complex as a late-night premiere of the Batman sequel `` The Dark Knight Rises '' played . The former neuroscience graduate student wore all-black , a ballistic helmet , a tactical ballistic vest , protective leggings , a throat and groin protector , and a gas mask , police say . And he carried an arsenal that included two Glock handguns , an AR-15 rifle , a shotgun and 6,295 rounds of ammunition , Bureau of Alcohol , Tobacco , Firearms and Explosives agent Steve Beggs has testified . `` He did n't care who he killed , '' prosecutor Karen Pearson told a judge during a preliminary court hearing in January , adding Holmes chose his venue carefully to cage his victims . `` He intended to kill them all . '' After the carnage and Holmes ' subsequent capture outside the theater , he was charged with 166 counts of murder , attempted murder and weapons violations . Rescue workers were n't prepared for chaos of Aurora shooting . Since his arrest , much of the in-court discussion has resolved around Holmes ' mental state . Judge Samour earlier this month accepted the defense 's plea of not guilty by reason of insanity . He was then taken to the Colorado Mental Health Institute in Pueblo for evaluation , and is expected to be back in Arapahoe County Jail on August 2 . Prosecutors in Arapahoe County announced in April they would seek the death penalty . Despite the notoriety of the mass shooting , the judge ruled Thursday that the empaneled jury will not be sequestered , as Holmes ' defense team requested . Making it so they could n't go home throughout the prolonged trial , Samour said , was an `` unnecessarily drastic , expensive and impractical remedy that ... will create an extreme and undue hardship for jurors . '' The judge also ruled against the defense 's attempt to prevent jurors from using phones or computers , barring their use in court but saying preventing them from using them outside is `` unreasonable and unfair . '' One thing jurors wo n't be able to see is restraints on Holmes . As someone accused of `` multiple violent crimes , '' Samour says that Holmes must be restrained carefully during his trial . But the judge said he need n't wear handcuffs or shackles . Instead , the judge ruled , Holmes will `` wear a harness under his clothing which will not be visible to the jury '' and will be anchored to the floor . CNN 's Carma Hassan contributed to this report .
NEW : Judge : The jury ca n't be sequestered , can use phones and talk outside court . Judge : The Dean will wear a harness that the jury ca n't see , the judge says . The trial of the man accused of killing 12 in a Colorado movie theater should start in February . The jury pool will have 5,000 people -- 1 of 90 residents in county -- spokesman says .