CENTENNIAL, Colo. – The photos were chilling and enigmatic, just like their subject. In the pictures, taken on his phone hours before the Aurora movie theater massacre, accused gunman James Holmes mugs for the camera and smiles as he holds a Glock under his face and displays his arsenal on his bed.

Prosecutors who displayed the pictures at a hearing that ended Wednesday argued the photos display “identity, deliberation and extreme indifference.”

Holmes’ attorneys — who have been setting up an insanity defense and said they might present testimony about the defendant’s mental health — decided not to call any witnesses.

A judge is due to rule by Friday whether prosecutors presented enough evidence to justify Holmes standing trial for more than 160 felony counts stemming from the July 20 attack, which killed 12 people and injured 70. Holmes, 25, may enter a formal plea that day.

The three-day hearing wrapped up just as the Colorado Legislature began its session and pledged to tackle gun violence, and Vice President Joe Biden met with families of victims as part of the White House’s own gun-control push.

Prosecutors presented the most detailed description of the attack and Holmes’ alleged months of preparation. But they never addressed the mystery of why Holmes opened fire six weeks after leaving a neuroscience graduate program.

Legal experts say evidence against Holmes is so strong that the case may end in a plea deal. That would make the hearing the only detailed presentation of the evidence that victims, their families and the public will hear.

Family members, who had a better view of Holmes’ face than the media did in the packed courtroom, said he smiled multiple times, especially when the photos were shown.

“He’s not crazy, he’s evil,” said Tom Teves, whose 24-year-old son Alex was killed in the attack. “He’s an animal.”