CENTENNIAL, Colorado: A bearded and bushy-haired James Holmes sat quietly as a packed courtroom waited Tuesday for a plea that could help shed light on a deadly shooting rampage he is accused of going on in a crowded Colorado movie theater last summer.

Instead, his lawyers told the judge they weren't ready to enter a plea - despite numerous delays since the July 20 attack that killed 12 people and wounded 70 at a midnight showing of "The Dark Knight Rises." The slaughter was one of several mass shootings last year that touched off an intense debate over gun control in the U.S.

After the defense lawyers said they couldn't enter a plea, a barely audible gasp rose from dozens of family members and victims.

"So how am I supposed to make an informed decision?" Judge William Sylvester asked pointedly, his gaze fixed on defense lawyer Daniel King, before the judge entered a not guilty plea on Holmes' behalf.

Legal experts said the defense's statement may be part of a larger strategy to avoid the death penalty. Holmes can still change his plea to not guilty by reason of insanity, and he can wait to do so until after prosecutors announce whether they will seek the death penalty.

"This just allows the defense to think through how they want to proceed," said Dan Recht, a Denver defense attorney who is following the case. "The odds are the prosecution is going to pursue the death penalty and literally Holmes' life is at stake, so they want to be able to think through all the pleas they can offer."

That makes it easier for the defense to plan its best case. Holmes could plead insanity and would wind up in a mental hospital indefinitely - and would never face execution - if the jury finds in his favor.

Holmes could also simply plead innocent, and he would not have to give prosecutors potentially incriminating medical records and statements made to doctors.

Attorneys on both sides left Tuesday's hearing without commenting. They are under orders from the judge not to speak about the case.

As he has done in past hearings, Holmes sat silently through the proceedings. He wore a red jail jumpsuit and sported a thick, bushy beard and unkempt dark brown hair. When he walked into the courtroom, he looked at his parents, Robert and Arlene Holmes. They sat silently at the front of the room and left without comment after the hearing.

Prosecutors say Holmes planned the assault for months, casing the theater complex in Aurora, amassing a small arsenal and rigging potentially deadly booby-traps in his apartment.

Then he donned a police-style helmet and body armor, tossed a gas canister into the theater crowd and opened fire, prosecutors said.

Nearly eight months later, the defense has dropped hints about Holmes' mental state but has given no clear statement on whether he would plead insanity.

Holmes, a former graduate student at the University of Colorado, Denver, had seen a psychiatrist at the school before the shootings.

Last week, his lawyers revealed that he was taken to a hospital psychiatric ward in November because he was considered a threat to himself. Holmes was held there for several days and spent much of the time in restraints.

Tuesday, there was another clue. At one point, in saying they weren't ready to enter a plea, King said, "We have ongoing work scheduled. We're doing the best that we can."

King said he couldn't reveal what the work was, or say when it would be finished. But he did hint that the defense might have its own expert conduct a mental evaluation of Holmes. He said that if Holmes pleads not guilty by reason of insanity, the court would have to order a state mental evaluation, and "whatever evaluations we're doing would be truncated."

The next step in the case comes April 1, when prosecutors announce their decision on the death penalty. The judge scheduled the trial to start Aug. 5, setting aside four weeks.

Whether and when Holmes will change his plea remains uncertain. His lawyers would have to ask the judge to set a hearing for a new plea.

Victims were relieved by the judge's decision to enter a plea for Holmes and keep the case moving forward.

"It's been since July," said Marcus Weaver, who was shot in the arm and who lost friend Rebecca Wingo in the attack. "We're just so thankful we're able to move forward."