El Salvador’s Cecot mega-prison was notorious long before the Trump administration’s recent decision to deport hundreds of alleged Venezuelan gang members there.

Human rights advocates warn that the deportees legal rights were violated as they were transferred to the CECOT, a mega-prison established by El Salvador’s President Nayib Bukele for his crackdown on gangs in the country. The facility, according to the Associated Press, can hold up to 40,000 inmates; up to 70 people are housed in a single cell.