CENTENNIAL, Colo. » At least 100 victims and witnesses of James Holmes’ deadly attack on a Colorado movie theater are expected to testify about the crime’s profound and continuing impact on their lives during a formal sentencing hearing starting Monday.

The three-day hearing gives survivors a chance to share their harrowing stories with the judge, but it won’t change Holmes’ sentence. Jurors already determined that Holmes will spend the rest of his life in prison without parole for the July 20, 2012, attack that killed 12 people and injured 70 others.

Judge Carlos A. Samour Jr. will formally sentence Holmes to life on 24 counts of first-degree murder — two for each of those killed. This week’s testimony will help him determine Holmes’ sentences on 141 other counts that include attempted murder and an explosives charge. Samour has not set a limit on the number of people who can take the stand.

Many victims testified during Holmes’ four-month trial about the terror and carnage he inflicted on more than 400 people who filled the seats at a sold-out midnight movie premiere of "The Dark Knight Rises" in suburban Aurora. Holmes, a former graduate student in neuroscience, slipped into the darkened theater, threw gas canisters into the crowd and opened fire with a shotgun, assault rifle and semi-automatic pistol.

Now, victims will be able to talk about the enduring harm he caused. They won’t be able to address Holmes directly but rather the judge.

Holmes will also have an opportunity to speak, though he declined to do so during his trial.

State corrections officials will determine where Holmes will be incarcerated after an evaluation that includes his mental health. That could last up to 60 days, Department of Corrections spokeswoman Adrienne Jacobson said.

Colorado prisons have an extensive mental health care system, and Holmes, who has been diagnosed with varying forms of schizophrenia, could wind up in the department’s mental hospital, the 250-bed San Carlos Correctional Facility in Pueblo.

The department has four levels of security for inmates, and those serving a life sentence, like Holmes, are usually classified at the highest or second-highest security level, Jacobson said. She said she couldn’t speculate on what kind of prison routine Holmes or any inmate would have.

Holmes’ attorneys blamed the massacre on his schizophrenia and psychotic delusions, and experts testified that it wouldn’t have happened if he were not seriously mentally ill.

Jurors quickly rejected his insanity defense, convicting him on July 16 of 165 felony counts. But they could not unanimously agree on the death penalty for Holmes.

After the trial, prosecutors said Holmes’ fate ultimately came down to a single juror, who said she could not morally impose a death sentence after hearing testimony about Holmes’ mental illness. The Aug. 7 verdict shocked many in the courtroom and the community, who assumed Holmes would pay with his life for one of the deadliest mass shootings in U.S. history.

Associated Press writer Dan Elliott in Denver contributed to this report.