Adding to the growing caselaw about the constitutional infirmities of immigration detainers, a federal district court in Texas concluded this week that a detainer lacking probable cause of criminal activity violates the Fourth Amendment. Trujillo Santoyo v. United States, No. 5:16-cv-00855-OLG, slip op. (W.D. Tex. June 5, 2017).

This case involved an individual arrested on criminal charges that were dismissed without a conviction. While lawfully jailed in the Bexar County Adult Detention Center during the pendency of the criminal case, ICE issued an immigration detainer against Trujillo Santoyo. Due to the detainer, he was not released even when the criminal charges were dismissed. He was released approximately six weeks later.

Officials of Bexar County, which includes San Antonio, readily comply with immigration detainer requests. Indeed, jail officials “assume[] that any subject of an ICE detainer request has been determined by ICE to have committed a felony or multiple misdemeanors.” Id. at 11. Despite the county’s assumption, ICE detainers do not even purport to indicate probable cause of criminal activity. At most, they provide an option for ICE officers to claim that there is probable cause to believe that the named individual is removable from the United States. But probable cause linked to removal is not equivalent to probable cause of criminality. As the court put it, “crucially, this refers not to probable cause to believe that a crime has been committed, but to believe that ‘the subject is a removable alien.’” Id. at 15.

The Fourth Amendment, however, requires that any arrest be supported by probable cause. But it’s not probable cause of just anything that is required. The Fourth Amendment, the court explained, requires probable cause of criminal activity. Because unlawful presence in the United States is not a crime, even if ICE meets the probable cause requirement it would not be sufficient to satisfy the Fourth Amendment. Indeed, “neither the mere removability of an individual nor the entry of a final removal order against them equates to a showing of probable cause that they have committed a crime,” the court explained. Id. at 15.