For now, the Mexican government remains tight-lipped about the motive for the attack. However, the attorney general’s office in the state of Tamaulipas said the theory that this was a case of mistaken identity was “strengthening”.
Officials wouldn’t comment on two specific suggestions – that a drug gang had confused them either for US-based rivals, Haitian drug gang members or people smugglers. But they said there were multiple and “diverse” lines of investigation, and that none was being ruled out at this stage.
Matamoros is caught between warring factions of the Gulf Cartel, as they battle for control of the so-called plazas – the drug smuggling routes north into the US.
Apparently unwitting, the group of friends from North Carolina drove their minivan straight into that maelstrom. Their ordeal lasted for four days.
As the US citizens were being moved between safehouses to prevent detection, the US Embassy issued a statement demanding their immediate release. For any Mexican cartel – or even a common criminal gang operating along the border – that will have spelt trouble.
The armed gang will have understood immediately that the full force of a joint operation by US and Mexican federal law enforcement was going to be turned in their direction. Had the motive been ransom, as is so often the case in Mexico, they will have realised it was now very unlikely to be paid.
Far easier, then, to simply turn the Americans over and deflect some of the intense heat bearing down on their gang.
“My guess is that’s the most reasonable explanation for what happened,” says Mexican drug war analyst, Alejandro Hope. “They might have had connections or contacts with local police and they just told their contacts where their safehouse was.”
Kidnappings in Mexico are disturbingly common. Last year, Mexico reached the horrific figure of 100,000 people disappeared or missing in the country. Most kidnappings are carried out with complete impunity, particularly in the case of undocumented immigrants travelling north to the US.
In comparison, this case was resolved incredibly quickly. Some Mexicans voiced frustration on social media at the speed with which such crimes are resolved when foreigners are involved.
“In under a week. And the thousands and thousands of kidnapped Mexicans?” wrote one Twitter user.
“That’s not untrue,” says Mr Hope. “Mexican institutions have a limited set of capabilities. But if they focus those capabilities on specific cases, yes, they can solve them.”
“It’s about visibility and political impact,” he says.
Clearly, in this instance, the political will in Mexico to find a solution couldn’t have been higher.
US Ambassador Ken Salazar met Mexican President Andrés Manuel López Obrador to discuss the matter, and said the US State Department had “no greater priority” than the well-being of its citizens abroad.
The case was brought to an end within 24 hours.