Via the ACLU:

Peter Sean Brown is a U.S. citizen who lives in the Florida Keys. He was born in Philadelphia and has lived in Florida for 10 years. Before this year, he had never heard of Immigrations and Customs Enforcement, or ICE.

That changed abruptly in April, when the Monroe County Sheriff’s Office held him in jail so that ICE could try to deport him — even though he’s a U.S. citizen. The ACLU, the ACLU of Florida, the Southern Poverty Law Center, and Gibson, Dunn & Crutcher LLP filed a lawsuit today against the sheriff’s office for violating Peter’s Fourth Amendment rights. His experience — being locked in jail away from his family, friends, and job to facilitate an illegal deportation — is a stark example of what can go wrong when local law enforcement does ICE’s bidding.