CARACAS, Venezuela (AFP)— Venezuelan prosecutors said Wednesday they were investigating the “forced disappearance” of a citizen detained in the United States, which under Donald Trump has deported hundreds of migrants to El Salvador and elsewhere.

Ricardo Prada, who worked as a deliveryman in the city of Detroit, was arrested in January as part of the Trump administration’s mass immigration crackdown.

In March, Prada informed a friend he was being held at a maximum security facility in Texas, “after which his whereabouts are unknown,” the public prosecutor’s office in Caracas said in a statement.

The United States has deported more than 250 Venezuelans to El Salvador, which is being paid by Washington to hold them in a notoriously harsh maximum security facility built to house gang members.

The prosecutors office, citing an article in the New York Times, said Prada was not in that group.

According to the newspaper, US authorities have said they deported Prada without revealing where to.

The Trump administration has paid El Salvador millions of dollars to lock up nearly 300 migrants it expelled, claiming they are criminals and gang members.

At least one of them, Salvadoran Kilmar Abrego Garcia, was found to have been wrongly deported, but both Trump and El Salvador’s President Nayib Bukele have said he cannot be returned.

Bukele has proposed an exchange of Venezuelan migrants deported from the United States for political prisoners held by President Nicolas Maduro’s government in Caracas.

Venezuela says it has repatriated 2,557 of its nationals under an agreement with the Trump administration.

Many were brought from the United States, others from third countries like Mexico where they became stranded under Trump’s strict anti-immigration measures.

Another flight carrying Venezuelans is expected back home later Wednesday.