CENTENNIAL — The man accused of murdering 12 people during the Aurora movie theater massacre is willing to admit to the killings if doing so will save his own life.

In a surprise motion filed Wednesday, lawyers for James Holmes said he has offered to plead guilty in exchange for a life in prison with no chance of parole. The offer was first made prior to the arraignment hearing earlier this month, according to the motion.

“Mr. Holmes is currently willing to resolve the case to bring the proceedings to a speedy and definite conclusion for all involved,” the lawyers wrote in their motion.

The move swings the spotlight onto prosecutors, who have said they will announce during a court hearing Monday whether they will seek the death penalty. Prosecutors are talking with theater shooting victims and their families to hear their opinions on capital punishment for the case.

Holmes’ attorneys wrote in their motion that prosecutors have not accepted the offer. Denver defense attorney Dan Recht said the offer narrows prosecutors’ decisions to a single question: Is death the only acceptable punishment in the case?

“Holmes can’t offer any more than he is offering,” said Recht, who has been following the case. “The choice for the prosecution could not be clearer.”

A representative for the 18th Judicial District attorney’s office said he could not comment on Wednesday’s motion because of a gag order in the case.

Holmes is accused of killing 12 people and wounding at least 58 others with gunfire in a darkened Aurora theater July 20. He faces 166 counts of murder, attempted murder and other offenses.

Earlier this month, a judge entered a not guilty plea to the charges on Holmes’ behalf, after his attorneys refused to enter a plea. At the time, they said they needed more time to study their options, and Wednesday’s filing provides fresh insight into the cause of their hesitancy.

By disclosing their offer in a court filing, Holmes’ attorneys have upped the pressure on prosecutors and, in effect, taken their plea directly to the public, Recht said. It is no coincidence that the motion was filed so close to the now-pivotal Monday hearing, he said.

In the filing, Holmes’ attorneys say they believe the case can be closed on Monday.

“It appears the only impediment to a resolution of this case would be if the prosecution chooses to seek the death penalty,” Holmes’ lawyers wrote in the motion.

If prosecutors decide to reject the offer, Holmes’ lawyers said they may launch a mental health defense and will “vigorously” defend Holmes at trial.

The ostensible reason for Wednesday’s filing was to ask the judge for more time to litigate motions prior to trial, and Holmes’ lawyers identified nine separate categories of issues they said would have to be argued about. The lawyers referenced the length of other recent death-penalty cases in Colorado — the trials, alone, in three recent cases each “took closer to four months” Holmes’ attorneys said — and they said the current trial date of Aug. 5 “would obviously need to be vacated.”

Prosecutors will have to weigh the pain of such a process on the victims with the value they might see in pursuing the death penalty, Recht said. Offering to plead guilty in exchange for life in prison without parole provides a guaranteed alternative for families reluctant to go through the years — or even decades — long march to execution.

“There’s finality,” Recht said. “They know Holmes will never be out on the streets again. And they don’t have to go through the agony and trauma of a drawn-out legal process.”

But prosecutors and victims may see life in prison without parole as inadequate punishment for such a terrible crime, said Karen Steinhauser, a Denver attorney who has been watching the case.

“They may believe the only appropriate sentence is the death penalty,” she said.

It is not an easy decision to make, Steinhauser said, and two high-profile cases show that it could go either way.

Last year, Jared Loughner, the man who killed six people and wounded 12 others, including former U.S. Rep. Gabrielle Giffords in Tucson, pleaded guilty to avoid the death penalty. But, in the case of Chuck E. Cheese killer Nathan Dunlap, an offer to plead guilty was rejected because prosecutors said he deserved death. Dunlap, Colorado’s longest-serving death-row inmate, is still awaiting execution.

Likewise, theater shooting victims and their families are unlikely to hold a single opinion on the death penalty for Holmes.

“From our family’s perspective, there are different opinions,” said Scott Larimer, whose son, John, was among those killed. “For me, as long as he never walks the face of the earth a free man, I will be happy.”

In comments made after Holmes’ arraignment earlier this month, shooting survivor Marcus Weaver said he believed Holmes should face the death penalty — but not if he pleaded guilty to the killings.

“To be honest,” Weaver said then, “I saw a human being today. And you can plead guilty and own up to it. Or you can plead not guilty and face serious consequences.”

In less than a week, Holmes will learn whether prosecutors agree.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold