They are there to look after their profit, and make sure that people don't step out of line, and we see regular examples of violence, kidnapping, extortion - and indeed holding people kidnapped in this country, and demanding people back home in the originating country, come up with more money.

BBC: More

Professor Monica Serrano from the Colegio de Mexico, a university in Mexico City, says the cartels' use of threats and extortion to boost funds is forcing people to leave their homes and in many cases make themselves "disappear".

BBC: Searching for Mexico's drug war 'disappeared'

Gangs such as MS-13 and 18th Street conduct business internationally, engaging in kidnapping, robbery, extortion, assassinations, and the trafficking of people and contraband across borders.

CENTERFORSECURITYPOLICY: Gangs and violence in Central America

"The model in people's heads right now is extortion, " Robert Reich, President Clinton's former labor secretary, tells me.

CNN: Borger: Where's the White House's tipping point?

The MQM (also involved in extortion in Karachi) complained that the government was targeting its people while letting the PAC get away with crime.

ECONOMIST: Violence in Karachi

But then it also appeared that some people within the revived party were active in heroin-trafficking, gun-running and extortion.

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