Updated

Police in southern Mexico are investigating how vendors in local markets obtained a grisly video that shows a mob beating and burning to death three suspected rapists.

A voice is heard on the video saying "Gasoline on everything!" and then the tape shows a man in flames, tied to a tree, writhing as a he apparently burns.

Tapes of the attack were being sold in street markets for 15 to 20 pesos ($1.15 to $1.50) apiece.

The Chiapas state attorney general's office said Wednesday all three men died. It is investigating both the mob attack and the sale of the video.

Voices on the tape allege the men were caught dumping the body of an Indian woman they raped and killed.