10 August 2011 Last updated at 19:06 ET

How Mexico's deadly gang tactics are spreading

By Linda Pressly
BBC Radio 4, Crossing Continents

Central American migrants in Mexico are vulnerable to kidnap by Mexican drug gangs while they wait for trains heading north to the US

Central American migrants heading north to the United States fear that they are increasingly in danger of being kidnapped and murdered by drug gangs expanding their criminal operations south from Mexico.

"People and body parts were scattered everywhere like stones. There was a torso here, a head there. Even the animals were chopped up."

Salvador, a boatman, is describing the scene at Los Cocos ranch in the region of Peten, in the north of Guatemala, where a gruesome massacre took place on 14 May, blamed on members of a feared Mexican drug gang known as the Zetas.

In this case, those targeted were 27 farm workers, killed in retribution for the farm owner's alleged unpaid drug debt.

But the fear among locals and migrants passing through on their way to the US is that the Zetas are expanding into this remote region.

When Salvador heard about the massacre, he drove there to take a look for himself.

"What I saw at Los Cocos, was just terrible," he says. "I don't want to talk about it a lot because I could get into trouble."

Written in blood

The Zetas have been operational in Peten since 2008, and the fear among local people is palpable.

Following the massacre, a warning was written in blood to the farm owner
"No-one talks about them," says Salvador. "They do their thing, and no-one knows what they are doing or who they are."

Illustrative of this fear, the guide who takes us to Los Cocos does not want to be identified, and we are escorted by a pick-up truck full of soldiers.

The ranch is deserted with just the sound of birdsong carrying on the hot, still air.

There are two rough, wooden huts, which were home to some of the murdered farm workers.

"If aside from making a profit from transporting drugs, the cartel can make money from extorting migrants or kidnapping them, they are going to do itâ€