UPDATE | Jury quickly convicts theater shooter James Holmes of murder

CENTENNIAL, Colo. (AP) — Colorado theater shooter James Holmes was convicted today in the chilling 2012 attack on defenseless moviegoers at a midnight Batman premiere after jurors swiftly rejected defense arguments that the former graduate student was insane and driven to murder by delusions.

The 27-year-old Holmes, who had been working toward his Ph.D. in neuroscience, could get the death penalty for the massacre that left 12 people dead and dozens of others wounded.

The initial phase of Holmes' trial took 11 weeks, but it only took jurors about 12 hours over a day and a half to decide all 165 charges. The same panel must now decide whether Holmes should pay with his life.

Dressed in a blue shirt and beige khakis, Holmes stood impassively as Judge Carlos A. Samour Jr. read charge after charge, each one punctuated by the word "guilty."

The verdict came almost three years after Holmes, dressed head-to-toe in body armor, slipped through the emergency exit of the darkened theater in suburban Denver and replaced the Hollywood violence of the movie "The Dark Knight Rises" with real human carnage.

His victims included two active-duty servicemen, a single mom, a man celebrating his 27th birthday and an aspiring broadcaster who had survived a mall shooting in Toronto. Several died shielding friends or loved ones.