CENTENNIAL — Worried about delaying the case and wary of traveling in “uncharted legal waters,” prosecutors on Thursday suspended their attempts to see a notebook that accused Aurora movie theater killer James Holmes mailed to his psychiatrist.

In a hearing expected to help determine whether the notebook is protected by doctor-patient privilege, Arapahoe County Deputy District Attorney Rich Orman instead announced that prosecutors were backing down on the issue. Orman said, whatever the judge decided on the notebook, the ruling likely would have been appealed to the state Supreme Court, prompting a months-long delay in the case.

Incremental rulings by 18th Judicial District Chief Judge William Sylvester during an earlier hearing on the issue had gone against prosecutors. And Orman said his side wasn’t interested in making Holmes’ case a guinea pig before the state’s highest court on the privilege question.

“These are uncharted legal waters,” Orman said. “As far as I can tell, this particular factual circumstance has never arisen before, anywhere.”

Prosecutors say Holmes put the notebook in the mail just hours before shooting started at an Aurora movie theater, killing 12 and wounding 58 more.

Previous reports from anonymous sources say the notebook contained plans for the massacre — information that could provide clues to Holmes’ state of mind before the attack. Prosecutors said they should be able to use the notebook as evidence, while defense attorneys said it was private and should be returned to Holmes.

One reason Orman said he was willing to drop the fight, for now, is that doctor-patient privilege is waived if a defendant pleads not guilty by reason of insanity or seeks to use mental health as a mitigator at sentencing.

“We think we are most likely going to get this notebook eventually,” he said.

Former Denver judge Christina Habas, who now works for the law firm Keating Wagner and represents some of the shooting victims, said there is no guarantee that an insanity plea would release the notebook.

“It is very possible,” she said, “but it’s not 100 percent certain.”

Part of the uncertainty lies with what is actually in the notebook and whether it speaks to Holmes’ mental state, she said.

For the time being, the notebook will remain locked in a court clerk’s office, though defense attorneys will be able to make copies of it under court and police supervision.

The prosecution’s decision cut short what was expected to be a day-long hearing in Holmes’ case. Holmes appeared in the courtroom with tightly cropped brown hair and a couple of days’ facial scruff, a marked contrast to the curly orange hair and bushy muttonchops of his previous appearances.

During the hearing, prosecutors added 10 more counts of attempted first-degree murder to Holmes’ charges, bringing his full slate to 152 counts in total. Prosecutors also amended 17 counts in what appears to be a move to correct misspellings and clerical mistakes, though redactions in the public documents make it unclear.

Jessica Fender: 303-954-1244, jfender@denverpost.com or twitter.com/Oh-Fender