President Trump’s decision to send migrants to a Salvadoran prison has set off a national debate in the U.S. In El Salvador, the phenomenon of men disappearing into prisons is all too familiar.

By Kristina Cooke and Ted Hesson Detainees at the Bluebonnet immigrant detention center in the small city of Anson, Texas, sent the outside world a message this week: S-O-S. With a Reuters drone flying nearby,