Ross returned with a second series, beginning in El Salvador where he met the 'most dangerous gang in the world', MS13 (Mara Salvatrucha) a gang started by migrant Salvadoran youths in urban Los Angeles. His next stop was Moscow where he came face to face with vicious Neo-Nazi gangs. Then Ross's examined Middle America's gang culture with a visit to St. Louis, Missouri, before taking a look at South Africa's ferocious Numbers Gang which thrives in the country's overcrowded prisons. Finally, following a recent spate of gang related incidents in London, Ross visited Peckham and Brixton and spoke to some of South London's most notorious gangs, including the Peckham boys and Cripset (South London Crips).
In this BAFTA winning series, Ross Kemp travels from El Salvador to Cape Town, St Louis to Moscow, and tracks down the criminals that lay down their law, finds out what makes them tick and what is being done to control them.
The fourth and final series kicked off with a special edition looking at street gangs in the Norris Green and Croxteth areas of Liverpool. Then Ross headed oversees again, travelling to Los Angeles, California to interview the Crips and the Bloods in the areas of Compton. Bulgaria was his next stop as he tried to find out who is actually behind the Roma Pick-Pocketing members. Next he looks at cocaine trafficking in Belize, before a 90-minute Kenya special, in which he investigated the Mungiki, an outfit labelled as the most dangerous gang in Africa.