Will Chalk

It's just before eight in the morning here in central Coolio Can, just outside one of the main shopping malls and another body on the pavement.

This one is very grisly.

It's a man who's been tortured.

There's a message taped to his body.

It seems to have photographs and some writing.

But clearly a message has been sent.

It gives you an idea of the extent, the brutality, the viciousness of the infighting within the Sinaloa cartel at the moment.

Meeting with the cartels is difficult at the best of times, but now even more so because they're right in the crosshairs of the United States and President Trump.

He's labelled them terrorist groups, he says their product, fentanyl and other drugs, are a weapon of mass destruction and he's promised that...

As well as bombing the cartels at sea, he's going to tackle them on land.

So they're feeling under threat like never before.

I'm about to go and meet with a group.

I'm going to have to leave my phone behind.

These men are vicious criminals fighting for an illegal drugs business worth billions.

They've gone to war after the son of one of their leaders betrayed another.

This power struggle is a fight to the death and they show little remorse.

They insisted we disguise their voices.

The civil war in the cartel has created a bloodbath in Culiacan.

Women are being killed.

Kids are being killed.