The American Civil Liberties Union said it planned to file a lawsuit Friday over what it said was Sheriff Lee Baca's blanket denial of bonds for thousands of people in local jails who had holds from Immigration and Customs Enforcement, the Los Angeles Times reported.
Local law enforcement can hold inmates for 48 hours at ICE's request through the federal Secure Communities program.
Prison expert James Austin said data from Baca's office revealed at least 20,000 inmates in Los Angeles County jails were subjected to ICE holds in 2011.
As many as 17 other California counties also deny bail for inmates with immigration holds, alleged John Bench, president of the Golden State Bail Agents Association.
British filmmaker Duncan Roy, one of five plaintiffs in the suit, said he spent nearly three months in the Los Angeles County jail because the sheriff's department rejected his repeated efforts to post $35,000 as bond.
The British newspaper The Independent said Roy was arrested in an alleged blackmail attempt against Malibu real estate agent and former boyfriend Chris Cortazzo, with whom he had a falling out over a property deal.
Roy said he repeatedly was told the only way he would be freed was if he pleaded guilty to a felony, which would have led to immediate deportation, despite his efforts to post bond. He eventually pleaded guilty to a misdemeanor charge.