The letter details hundreds of patient-on-patient assaults, suicide attempts and staffing shortages that result in patients not receiving the proper amount of medication with little accountability by caretakers.

Officials at Patton the nation's largest facility for mentally ill criminals awaiting trial or serving sentences for insanity verdicts responded by pointing to new programs already under way and requests for funding to beef up staffing levels.

Patton spokeswoman Cindy Barrett said the letter wasn't unexpected. She said hospital employees are doing the best they can with patients who can be, to say the least, difficult.

"When the Department of Justice comes in, one incident is too many. It's too many for us, too," Barrett said. "We have a unique challenge working here, to balance quality of care with patient and staff safety."

The letter follows the Justice Department's visit in December, which was preceded by more than 500 patient-on-patient assaults in the six previous months and a "high number" of patient suicide attempts, according to the letter.

What's more, those and other disturbing incidents aren't adequately tracked, the letter says. No follow-up changes or interventions are taken to prevent more injuries or deaths in the future.

Psychiatrists are rushed and diagnose patients without having enough information for accurate assessments, the Justice Department found. This results in inappropriate medication regimens and treatment plans, according to the letter, slowing their rehabilitation and delaying their eventual discharge.

The patient population at Patton is about 1,500. Patients are sent to the hospital when they are determined to be unfit to stand trial because of their mental state, or when found not guilty of a crime by reason of insanity.

The department began its investigation in April 2004. It conducted an on-site inspection of Patton in December and sent its report to the governor May 2.

That day, the Justice Department announced it had reached a settlement with California concerning civil-rights violations at Patton and three other state hospitals.

The settlement requires a five-year plan for improving patient care and rehabilitation.

In the settlement, the Justice Department said "significant civil-rights violations" were occurring at Patton and Metropolitan State Hospital in Los Angeles, Napa State Hospital in Napa and Atascadero State Hospital in San Luis Obispo.

Patton and Atascadero are not officially part of the settlement because their investigations are ongoing. But because the settlement requires improvements statewide, patients at all the hospitals will benefit, officials say.

Patton officials have asked to add 138 therapists, psychologists, psychiatrists and other team members to the 2,200 employees at the hospital now. They've made their request to the governor, hoping he will approve the $43 million new annual spending in the next fiscal year's budget.

"The more clinical staff we have, the more variety of groups we can offer," Barrett said. "We'll have more teams so their case loads will be less.

"It can't hurt."

The extensive reforms required by the five-year agreement are meant to ensure that patients are protected from harm and provided adequate treatments as required by their particular mental conditions.

Barrett said the hospital is changing over to a "recovery philosophy" in which patients take a more active role in their treatment.

But it's been slow going, she said, and the institution is in the second year of the five-year transition.

"For the past two years, we've been trying to get to the point where the Department of Justice wants us to be," Barrett said. "We're trying to fine-tune things now."

Eric Holland of the Department of Justice, in an e-mail, wrote there is nothing novel in the new model.

"Having said that, the department applauds the state's commitment, reflected throughout the agreement, to obtain individuals' active participation in the treatment process," Holland wrote.

Regardless of conditions at the hospital, the courts will continue to send defendants there when they are deemed mentally unfit to stand trial, said Larry W. Allen, presiding judge for San Bernardino County Superior Court.

"The court is required by law to send certain individuals to Patton, and that's not going to change," Allen said. "More treatment would hopefully get them back to us sooner, but it doesn't directly involve what we do."