SAN FRANCISCO » David Theisen keeps his legal papers in a frayed yellow envelope in his tiny transients’ hotel room, a toilet down the hall, the covers of his beloved comic books, with titles like "Dark Mysteries" and "Vault of Horror," lining the drab walls.

A lot has changed in the year and a half since Theisen, 52 and homeless, threatened to kill himself with a butcher knife and ended up in a Las Vegas psychiatric center. After one night, Theisen found himself on a bus to San Francisco, several sack lunches and a day’s worth of medication clutched in his lap.

"Technically, they shouldn’t have been allowed to send me anywhere," Theisen said. "They should have put me in a little room until I got better."

Now, Theisen is at the center of a class-action lawsuit brought this month by San Francisco’s city attorney, Dennis Herrera, against the state of Nevada on behalf of 24 mentally ill and homeless people. They were all, like Theisen, bused out of Nevada and left on the streets of San Francisco with little or no medication.

But that is just a small sampling, Herrera says, of the estimated 1,500 people who were bused all over the country in recent years from the state-operated Rawson-Neal Psychiatric Center in Las Vegas and other Nevada institutions, 500 of them to California.

"It’s horrifying," Herrera said. "I think we can all agree that our most vulnerable and at-risk people don’t deserve this sort of treatment: no meds, no medical care, a destination where they have no contacts and know no one."

But what makes it "even more tragic," Herrera said, "is that on top of the inhumane treatment, the state of Nevada was trying to have another jurisdiction shoulder the financial responsibility for caring for these people."

Attorney General Catherine Cortez Masto of Nevada, who has several weeks to respond to Herrera’s lawsuit, has declined to comment in the meantime.

Mary Woods, a spokeswoman for the Nevada Department of Health and Human Services, laid out the state’s position in an email. Outside a handful of instances, the state believes that its Client Transportation Back to Home Communities program was operated properly and that it is not dissimilar from programs in other jurisdictions, including San Francisco.

Hospitals in several cities have programs intended to reunite discharged psychiatric patients with their families and hometowns. Where abuses occur, Herrera and others say, is when patients are shipped off with little or no oversight about where they are going and what will happen once they get there.

Nevada officials say that besides a single, well-documented case, they believe that the Rawson-Neal staff followed proper release procedures in almost all of the remaining cases they have investigated.

That single case, involving a man named James F. Brown who was sent by bus to Sacramento, a city where he knew no one, from the Vegas hospital in February, was the subject of an article in The Sacramento Bee.

That newspaper article not only prompted the San Francisco city attorney’s office to look into the Nevada policy, but also led to a federal investigation.

"This has certainly elevated attention of a practice that, frankly, has probably gone on for many years in a number of states," said Ronald S. Honberg, legal director for the National Alliance on Mental Illness in Washington. "We’ve never done a study, and I’ve never seen one anybody else did, but we have certainly heard over the years a number of stories that this sort of practice goes on. It’s something we refer to, euphemistically, as Greyhound therapy."

Theisen’s experience began when he and another homeless man tried to hitchhike across the Mojave Desert from Las Vegas to San Diego. They made it about 45 miles to the small town of Primm, little more than a cluster of casinos.

The two men, desperate and hungry, ordered a meal and then ran before the bill arrived. They did not make it. His friend was arrested, but Theisen went to a pay phone and called the authorities. "I told them I had a knife and was going to kill myself," he said. "After the dine-and-dash, I just gave up."

He begged not to be sent back onto the streets of Las Vegas, he said, and did not care where they shipped him. "They asked me what kind of work I had done, and I said I was a cook," he said. "So some young woman said, ‘Well, there are a lot of restaurants in San Francisco.’"

Theisen said he eventually wound up at the Rawson-Neal facility, where he spent the night. The next morning, he said, his doctors sent him to a Greyhound station with seven sack lunches and a day’s medication for the 14-hour ride. He arrived with three lunches left and $30 on a food stamps card, and bounced from shelter to shelter until he managed to get a room in a downtown transients’ hotel.

Rumors of such journeys had become part of California homeless lore.

"In San Francisco, it’s been urban myth for decades that this sort of practice was going on," Herrera said. "But this is the first instance that I am aware of where we have been able to document a state-supported and state-sanctioned effort."

Woods, the spokeswoman for Nevada’s health agency, said that from July 1, 2008, to March 31, the state bought out-of-state bus tickets for 4.7 percent of the patients it discharged, an estimated 1,473 people.

"The findings show there were 10 instances in the course of five years where there was not enough documentation to know for certain if staff confirmed there was housing/shelter and supportive services at the destination," she said.

The federal Centers for Medicare and Medicaid Services, however, said last month that its inquiry showed a more widespread problem. About 40 percent of the mental patients discharged by the hospital went into local homeless shelters or were shipped elsewhere, the federal investigators said, and most of those were sent directly to a Greyhound bus station with a ticket but without proper documentation or instructions on what they should do when they arrive.

Some medical staff members at Rawson-Neal were fired after the furor following the Bee report, Woods said, and the hospital strengthened its discharge protocols. Gov. Brian Sandoval of Nevada pushed the Legislature to approve, which it did, $30.4 million in additional mental health spending, including $2.1 million for Rawson-Neal.

Herrera is not satisfied. He wants proof that the new protocols are in place, as well as compensation for all the city has spent to care for the patients from Nevada. He is also talking to other California cities about joining him in the lawsuit.

"I am hopeful that shining a light on this will also shine a light on other jurisdictions around the country to make the point that this is not going to be tolerated," he said.

It has been a tough year for Rawson-Neal. In July, it lost its accreditation, a decision that it did not fight. Of greater concern is a move by federal officials to possibly end Rawson-Neal’s eligibility for Medicare financing.

Theisen now subsists on $100 in assistance from the city every month, which with his free room, is just enough if he is careful. He gets the medication he needs for his depression and spends his days at the public library or roaming the city, looking for work as a cook. The important thing is that now, for the first time, he can see a way forward.

"I guess they shouldn’t have done what they did in Nevada, but I cannot say enough about what this city has done for me," he said. "It’s awesome, really. I have to struggle, yes, but otherwise life is good. I don’t wake up sad anymore."

© 2013 The New York Times Company