Accused Aurora theater shooting suspect James Holmes listens at his arraignment in Centennial, Colorado in this file photo taken March 12, 2013. [Photo/Agencies]

DENVER -  Prosecutors said Thursday they are not ready to accept an offer from Colorado theater shooting suspect James Holmes to plead guilty in exchange for avoiding the death penalty.

Legal experts say the case pivots on whether Holmes was legally insane when he opened fire in a packed theater in Aurora, killing 12 people.

In a court filing, prosecutors criticized defense attorneys for publicizing Holmes' offer to plead guilty, calling it a ploy meant to draw the public and the judge into what should be private plea negotiations.

They say the defense has "steadfastly and repeatedly" refused to provide key details they need to consider a plea.

No agreement exists, and one "is extremely unlikely based on the present information available to the prosecution".

Holmes' attorneys disclosed in a court filing Wednesday that their client has offered to plead guilty to killing 12 people at a midnight screening of the latest Batman movie, but only if he wouldn't be executed.

Prosecutors say defense attorneys are trying to pull the judge into a possible plea agreement, and criticized comments to the media, including The Associated Press, from Doug Wilson, who heads the state public defenders' office.

Wilson didn't immediately return a call Thursday.

George Brauchler, the district attorney, is scheduled to announce Monday whether he will seek the death penalty for Holmes. Brauchler hasn't publicly revealed his plans. He has refused repeatedly to comment on the case, citing the gag order and his spokesman didn't immediately return a call Thursday evening.

Pierce O'Farrill, who was shot three times, said he would welcome an agreement that would imprison Holmes for life. The years of court struggles ahead would likely be an emotional ordeal for victims, he said.

"I don't see his death bringing me peace," O'Farrill said. "To me, my prayer for him was that he would spend the rest of his life in prison and hopefully, in all those years he has left, he could find God and ask for forgiveness himself."

A plea bargain would bring finality to the case fairly early so victims and their families can avoid the prolonged trauma of not knowing what will happen, said Dan Recht, a past president of the Colorado Criminal Defense Bar.

"The defense, by making this public pleading, is reaching out to the victims' families," he said.