MEXICO CITY – The five men were left prostrate on the sidewalk outside their black pickup truck, their shirts pulled over their heads, bare torsos pressed against the ground, their bound hands spread before them almost in supplication.

The handwritten letter on the truck’s windshield read like a formal, albeit chilling and remarkable apology: the Gulf Cartel Scorpion Group was very sorry that their members accidentally shot and killed two Americans and a Mexican bystander while kidnapping two more US citizens.

The men were being offered up to the authorities, the letter said, to make amends for disturbing the peace. On Friday, Mexican prosecutors charged the five men in connection with the abduction and killings.

While Mexican drug cartels thrive in a vacuum of law and order that persists inside Mexico, there is an unspoken rule that many members of organised criminal groups are careful not to cross: Do not touch Americans.

The United States takes attacks on its citizens seriously, and the response to such violence, on both sides of the border, can be ruinous for a Mexican criminal group.

“When American citizens are targeted, it brings pressure from the US government, they get their security agencies involved and then start putting pressure on Mexico to act,” said Professor Cecilia Farfán Méndez, a Mexico security researcher at the University of California, San Diego.

“The worst thing for the cartels is that they have to dedicate resources to countering the Mexican authorities that mostly leave them alone,” she added. “It’s not good for business.”

Cartels can often outgun the Mexican authorities or simply buy their cooperation, but they know that prodding the US government into action can hinder their ability to operate. And in recent years, organised crime has come to rely on the Mexican government’s inability to effectively control it.

‘Hugs, not bullets’

Mexico’s President Andrés Manuel López Obrador came to office promising a new approach to quell violence: avoiding direct confrontation with criminal groups, in favour of addressing the root causes of criminality like corruption and poverty.

But his strategy, which he branded with the slogan “hugs, not bullets”, has done little to tame extraordinary levels of violence or diminish the ever-expanding power of cartels that traffic drugs and migrants across the US border and terrorise Mexicans at home.

In many communities, Mexicans live in fear of criminal groups that commit daily acts of violence that by and large attract little attention outside the country. And while cartels avoid deliberately targeting Americans, their business model rests on shipping narcotics north that have helped fuel an epidemic of drug deaths in the US.

The Biden administration has been reluctant to openly criticise Mr López Obrador, including over security problems in Mexico, wary of threatening his cooperation on migration.

But the attack on four Americans last week became an international scandal, increasing pressure on the US government to do more to combat crime south of the border, and eliciting calls from Republican lawmakers to authorise US military force to confront the cartels.

The calls prompted an outcry in Mexico, with officials demanding that the US government respect their sovereignty, but also forcing the Mexican government to respond. This week, hundreds of additional Mexican security forces were deployed to Matamoros, the border city where the attack on the four Americans unfolded.

The Camarena repercussion

That kind of outsize attention is precisely what criminal groups want to avoid, and they have largely left American citizens alone ever since the 1985 abduction, torture and brutal slaying of Mr Enrique Camarena, a DEA agent, who disrupted cartel operations at the time and drew their bloody ire.

Mr Camarena’s mutilated body was found wrapped in plastic bags on a ranch in western Mexico, his hands and feet bound and his face unrecognisable after multiple blows with a blunt object.

In its quest for justice, the DEA launched Operation Legend, one of the largest homicide investigations undertaken by the agency, which revealed that the Mexican authorities covered up Mr Camarena’s murder and destroyed valuable evidence. The operation led to the arrest of cartel members and forced others into hiding.

The message was clear: Going after American law enforcement agents would have far-reaching consequences for criminals and their accomplices in the Mexican government.

Cartels eventually learnt that even mistakenly killing US citizens could be costly.

In 2019, an organised crime group opened fire on Americans and Mexicans who were driving through the northern state of Sonora, killing three women and six children, part of a Mormon group that lived in Mexico. Some of the victims were burned alive in their cars, about 113km south of the US border.

In the aftermath, several people were arrested, including a Mexican police chief believed to be protecting local criminal groups. The Mexican government claimed the deadly attack could have been a case of mistaken identity and related to a conflict between two criminal groups vying for control.

This week, the Mexican authorities were said to be considering a similar explanation for the kidnapping and slaying of the Americans in Matamoros, investigating whether it was another case of mistaken identity. NYTIMES