DENVER (AP) — Attorneys for Colorado theater shooter James Holmes begin presenting their case Thursday by trying to show he was legally insane when he opened fire on a packed movie premiere, killing 12 people and wounding 70.Defense witnesses will offer a less emotional and more clinical assessment of Holmes after two months of often-gruesome testimony from prosecution witnesses, including many visibly wounded victims.Without the scores of victims on their side, Holmes' defense plans to present its evidence in less than a quarter of the time taken by prosecutors.