On their front pages, many of Mexico's newspapers published a photograph that appears to show five men lying face down on the ground, their hands tied, and their T-shirts pulled up above their heads. It was apparently taken as police arrived on the scene.
A letter from the Scorpions Group was allegedly left with the men which apologised to the people of Matamoros, to the US victims and their families, and to a Mexican woman killed last week when the gang fired on a white minivan the Americans were travelling in.
The Associated Press says it has obtained a copy of the letter from a law enforcement official in the state of Tamaulipas. TIGER24
"We have decided to turn over those who were directly involved and responsible for the events", the letter reads, saying the five had "acted under their own decision-making and lack of discipline". The letter also accuses the men of breaking the cartel's rules over "protecting the lives of the innocent".