Two groups of inmates being held in a unit at the Los Angeles County jail in Castaic, California, were filmed sharing water bottles and a face mask.
The behaviour, according to the Los Angeles County Sheriff, resulted in almost half of the inmates in the unit later testing positive for the virus.
“Somehow there was some mistaken belief among the inmate population that if they tested positive there was some way that it would force our hands and release inmates,” said LA County sheriff Alex Villaneuva.
“That is not going to happen.”
In April, officials became alarmed by a sudden spike in suspected cases at the North County Correctional Facility. There had been no coronavirus cases until then.
When they studied surveillance footage from a day-room, they saw inmates passing around and sniffing a face mask and drinking from a shared Styrofoam cup.
Investigators then found footage of a second incident where inmates were taking sips from the same bottle of hot water, moments before they were due to have their temperatures checked by a nurse.
Within weeks, 30 inmates – out of a population of around 50 in the unit – had either tested positive or fallen ill.
Villaneuva said: “It is sad to think that someone would deliberately try to expose themselves to COVID-19.”
He said no one had admitted trying to spread the virus but that “their behaviour convicted them”. He said inmates usually “jealously guard” their own drinking mugs for fear of contracting an illness.
The Los Angeles County jail system is the biggest in the world and more than 5,000 inmates have been released during the coronavirus crisis. To qualify, inmates must be within 60 days of their scheduled release.
An investigation into the attempt to spread the virus is now being carried out and inmates could face criminal charges.
The sheriff said it was “deeply disturbing” that they would imperil themselves, other inmates and staff.
“There’s a reason why they’re behind bars in the first place, because they violate the norms of society.”