“In most respects, ICE facilities operate with less consistent oversight and legal accountability than state or federal prisons or local jails,” Brinkley-Rubinstein said. “ICE detention facilities and people that run them tend to be much less transparent about their operations.”

Several immigrant detainees described high tension and anxiety at the remote, hastily constructed facility over a lack of information, recreation and access to medication.

Some people detained at the facility have violent criminal histories. But data and news reports about the first month’s arrivals show the majority of Alligator Alcatraz’s detainees do not have U.S. criminal convictions.