After news broke earlier this year that a psychiatric hospital in Las Vegas was loading mental patients on Greyhound buses and shipping them out of the state to San Francisco and L.A., City Attorney Dennis Herrera vowed to take legal action. Today, Herrera filed a class action lawsuit after Nevada refused to pay the $500,000 psychiatric bill that Herrera sent last month.

The City Attorney's class action lawsuit was filed on behalf San Francisco as well as other California counties that ended up with the unwanted patients. The Nevada Attorney General's office, on the other hand, claims Herrera doesn't have the evidence to back up the suit and that the Sagebrush state actually subsidized some care for former Californians:

[Nevada Chief Deputy Attorney General Linda] Anderson countered that Herrera has not provided “sufficient explanation of your legal theory or standing for the initiation of a lawsuit by you on behalf of the ‘affected California cities and counties.’ ”

She also pointed in her letter to recent press accounts of a mental health patient sent from California to a Nevada hospital, and said that Rawson-Neal had provided care for 771 patients from California during the period Herrera is investigating, July 1, 2008 to March 31, 2013.

“Therefore, it could be argued that … the taxpayers of the State of Nevada have subsidized the State of California over $6.2 million during this same period,” Anderson wrote.

To that point, Herrera says mental patients voluntarily leaving California for Nevada is a different situation than a hospital giving recently discharged patients one-way bus tickets. The practice was uncovered during an investigation by the Sacramento Bee that proved the Rawson-Neal Psychiatric Hospital in Las Vegas had dumped some 1,500 patients total since 2008, with 500 or so of those ending up in California. The Chronicle followed up with their own report of a man who ended up in San Francisco after leaving a Reno hospital.

Previously: S.F. Investigating Nevada Hospital For 'Dumping' Mental Patients
[City Attorney]