The scar on Zac Zimmerman's left arm is still visible. It's a daily reminder of his suicide attempt, which led to a string of events that landed him in jail. He said he was paranoid and felt like hospital staff were out to get him.

Zimmerman tried to choke a nurse. The 22-year-old was charged with second- and third-degree assault in the 2013 incident. After two weeks in the psychiatric unit, he went to jail for three months.

He wasn't sentenced to three months; that was how long it took for the court process to play out.

"My anxiety was to the point that I couldn't move my hand, had no feeling in it," he said. "When I get nervous I chew my nails. I bit my fingernails all the way out. It was that bad."

Zimmerman is one of thousands of Minnesotans in jail who suffer from mental illness. While in jail, some stop taking their medication. Their stays behind bars may last for weeks, even months.

Public safety officials have complained for years that jails are de facto holding facilities for the mentally ill. Legislation in 2013 that aimed to reduce the length of time those inmates spend behind bars has made some progress, but hasn't solved the problem.

Patient advocate Kim Davis, right, with Duluth's Center for Alcohol and Drug Treatment listens to Zac Zimmerman, left, talk about his struggle with mental health Feb. 4 at the St. Louis County Courthouse. Derek Montgomery for MPR News

The so-called "48-hour rule" requires that certain inmates committed to the state Department of Human Services receive treatment within two days of a judge's order. Judges can issue commitment orders when patients appear to be a danger to themselves or others.

According to Minnesota Department of Human Services data, 25 percent of those subject to the 48-hour rule missed the window, which means they were in jail longer than the law allowed.

Issues with the mental health system have prompted the state legislative auditor's office to look into how people with mental illness fare in the criminal justice system. The office plans to release a report Thursday at a Senate committee hearing.

The report is expected to detail whether jails provide mental health services consistent with state laws and whether the state provides adequate treatment in the community to reduce repeated offenses. It is expected to raise questions of whether the Department of Human Services has complied with the 48-hour rule.

Since July 2013, when the law took effect, through January of this year, DHS admitted 573 jail inmates to state-operated mental health treatment facilities. Of those, 323 were subject to the 48-hour rule. The state found beds for 243 of them, while 80 missed the window, according to DHS.

Hennepin County Sheriff Rich Stanek argues that jails aren't medical facilities appropriate for treating mentally ill inmates. He said DHS officials need to secure funding to open up more beds for people with mental illness.

"They know perfectly well that in some cases they are skirting the law, or just outright not complying," Stanek said.

DHS officials blame most failures to get people into treatment quickly enough on law enforcement's slow transfer of inmates.

Zac Zimmerman is one of thousands of Minnesotans suffering from mental illness. Derek Montgomery for MPR News

According to DHS, slow transfers by law enforcement were responsible for 61 inmates' detention beyond the two-day limit. In 10 cases, the cause was a lack of available beds. The remaining nine cases were ascribed to "staff errors or are still being reviewed."

Department of Human Services Commissioner Emily Johnson Piper declined an interview request for this story, but she sent a statement.

"We all share deep respect for our state's mental health professionals, law enforcement partners and other stakeholders," Piper said. "And we are hopeful there will be broad support for the significant investments needed for our Direct Care and Treatment facilities and programs."

Jail transfers add stress to secure psychiatric facilities

While sheriffs and county attorneys say mentally ill patients languish in jail longer than they should, staff at the Anoka-Metro Regional Treatment Center say their facility has been flooded with violent patients coming from jail since the 48-hour rule became law.

In April, the state began to decrease the capacity at the state's second-largest psychiatric hospital from 110 to 95 beds because of staffing and patient safety issues.

The hospital is at capacity. But the legislative auditor found 30 to 40 percent of the patients there no longer needed that hospital level of care. For reasons that were not made clear, they need to be detained in a secure facility.

"People have different problems at different times and need to be treated specific to what they need at that point in their lives," Legislative Auditor Jim Nobles said. "And that is particularly challenging."

No law to limit the legal process

Even with the 48-hour rule, state law doesn't limit the length of time mentally ill inmates stay in jail after they're booked and before a commitment order is issued. The 48-hour rule kicks in after a judge issues a commitment order.

It takes time to get inmates evaluated and diagnosed with a mental illness.

"That's not going to happen in 48 hours," said St. Louis County Judge Sally Tarnowski.

Judge Sally Tarnowski presides over one of three mental health courts in the state. Derek Montgomery for MPR News

Hennepin County District Judge Jay Quam estimated that half of those who get evaluated and are found incompetent don't fit the commitment order criteria, and therefore aren't subject to the 48-hour rule.

"They're so mentally ill that they're not able to be handled in the criminal justice system, they're incompetent," he said. "But because there is a different standard for commitment they may not satisfy that and they end up just being sent out in the street to begin the process again."

The legislative auditor's report will focus on people with mental illness who are taken into custody by law enforcement. It's expected to look at existing community-based facilities and address whether they're fit to serve that population.

Zimmerman, the 22-year-old who attacked a hospital nurse, wasn't subject to the 48-hour rule. He accepted a plea deal that called for three months in a mental health treatment facility, five years' probation and participation in a mental health court that helps him navigate the system.

He'd like to travel again. Before his suicide attempt, he would jump on trains, hitchhike and sleep in farm fields.

"There is a right way to do it and a wrong way to do it," Zimmerman said. "I know what happens or what can happen if I stop taking medication. I just feel that it keeps me stable."