Authorities in San Francisco say their hands are tied when it comes to stopping a woman who has been breeding hundreds of rats in her home and then releasing them into public parks.

Police say that when they last checked in on the woman's room at a residential hotel, she was living with 300 rats in deplorable conditions.

"We found a small room that was completely infested with rats that had actually burrowed into the walls and gone into other units as well,” Animal Care and Control Captain Denise Bongiovanni said.

The woman's social worker says the woman has a mental health issue and has been breeding rats since 2011. Authorities say the woman moves when she is confronted about the problem.

Bongiovanni says the department has adopted out some of the tame rodents and exterminated sick or feral ones over the years.