At a briefing, Sheriff Alex Villanueva showed surveillance videos from two dormitory units at the North County Correctional Facility in Castaic.
The footage captured inmates in one unit sharing a container of hot water and others in a second unit sniffing a mask.
The sheriff said the inmates used hot water to try to raise their temperatures just before a nurse checked them. An elevated temperature is a symptom for coronavirus.
Villanueva said the inmates mistakenly believed that if they were infected they would be freed.
“It's dismaying and it's disheartening,” he said.
In mid-April, the North County Correctional Facility didn't have a single COVID-19 case. Days later, nine inmates were flagged as being potentially sick, according to Bruce Chase, the department's assistant sheriff of custody operations.
Deputies had been reviewing surveillance video trying to see if the inmates were socially distancing and using their masks when “lo and behold, we stumbled across footage that was very troubling to us,” Chase said.
The mid-April video showed a group of inmates passing around a mask and sniffing it. As authorities were investigating that incident, they found out about a second case where inmates were sipping from the same container of water in late April.
Within two weeks, 21 inmates in the water container case had COVID-19 and nine prisoners from the mask incident were sick, Chase said.
He said there's no evidence the mask or water container came from an infected inmate, and the prisoners may have just been trying to spread the virus if they had it. No inmates have admitted to a scheme.
Chase said his deputies need to better educate the inmates about the virus and the severity of their actions.
“We're responsible for their care,” Chase said. “That includes protecting them from themselves.”
The sheriff’s department, which oversees the nation’s largest jail system, has released more than 5,000 inmates during the pandemic to create more social distancing.
The department has freed inmates using several qualifications, including if they are within 60 days of release. Inmates who have tested positive for the virus can be released.
Inmates who are awaiting COVID-19 test results are being held in a downtown jail’s hospital ward or being treated at a county hospital if their symptoms are more severe.