More than 2,500 members of the Mara Salvatrucha street gang, or MS-13, are serving time in El Salvador's Ciudad Barrios prison.

Jose Luis Mendoza, a founding member of the gang, which originated in west Los Angeles in the early 1980s, showed the BBC around the prison - a facility built to house just 800 inmates.

Deported three times from the United States, Jose Luis Mendoza is now serving 52 years for murder in the Salvadoran prison.

Video journalist Dave O'Neill

Find out more on Crossing Continents on BBC Radio 4 on Thursday, 22 November at 11:00 GMT and Monday, 26 November at 20:30 GMT. You can listen again via the Crossing Continents website or via the Crossing Continents podcast.