Documents show taxpayer costs for the Colorado theater shooting case have risen to more than $2.2 million before the trial has even started, and that doesn't include legal costs for defendant James Holmes.

Officials in the Denver suburb of Aurora, where the July 2012 massacre occurred, said Wednesday they have spent more than $928,500 on the case, including $517,000 in overtime pay for police and other city employees.

Prosecutors previously said they've spent $920,000 on the case. Court officials say they have spent $435,000, mostly on courtroom security.

Holmes' taxpayer-funded lawyers refuse to disclose their expenses, citing attorney-client privilege.

Holmes pleaded not guilty by reason of insanity to charges in the killing of 12 people and injuring of 70. His trial is expected to start April 27.