The Mexican government has invited the FBI to participate in the investigation into the attack on three carloads of women and children from an isolated community just south of the Arizona border.
In a joint statement Sunday, Mexico’s Security and Citizen Protection Secretariat and Foreign Relations Secretariat said the FBI would be invited to "accompany" investigators from the federal prosecutor’s office examining the shootings that killed nine people Monday.
Authorities have said gunmen opened fire on the families from a fundamentalist community as they drove through a remote and rugged region — killing three women and six children. All held U.S. and Mexican citizenship, relatives said.
Officials at the FBI confirmed that they would be "providing assistance at the invitation of the Mexican government with the investigation into the recent attack against American citizens."
FBI agents working in Mexico would be unarmed, while working alongside Mexican investigators, according to the Mexican agencies' statement, and would "perform certain binational, technical support activities."
The Mexican government described its collaboration with the FBI as "broad" and said it occurs in "various federal Mexican institutions responsible for the pursuit of justice."
The killings in northern Sonora state came as Mexico confronts a rising tide of violence. The homicide rate reached a record high of more than 33,000 in 2018, while violence stemming from cartel conflicts and crimes such as “huachicoleo” — gangs pilfering gasoline from pipelines and fencing it — have turned to once-placid pockets of the country into no-go areas.
On Friday, the U.S. government increased its security alert to prohibit personnel from traveling to the city of Chihuahua, capital of the state of the same name, some 235 miles south of El Paso. At least 38 homicides in Chihuahua state, which neighbors Sonora, were reported in just 30 hours prior to the warning being issued.
Also, 16 vehicles and buses were burned in Ciudad Juárez, which sits next to El Paso, according to Mexican media. Those attacks left nine workers traveling to their factory jobs with severe burns. They were blamed on a gang known as Los Mexicles, which wanted to create chaos in the city and thwart the revision of a local prison, the newspaper La Jornada reported.
Ten more bodies were also discovered over the weekend in a mass grave being exhumed in Puerto Peñasco, also known as Rocky Point, on the Gulf of California near the Arizona border.
The slayings of the women and children, however, captured intense international attention and cast a critical eye on the security policies of Mexican President Andrés Manuel López Obrador. He has proposed calming the country by combating what he considers to be the underlying causes of crime: poverty and corruption. He speaks often of "hugs, not bullets."
But while the fundamentalist communities in the area, historical offshoots of the Church of Jesus Christ of Latter-day Saints, have made homes in the region for generations, the victims were nonetheless U.S. citizens.
With President Trump offering support — “The United States stands ready, willing & able to get involved & do the job quickly and effectively,” he tweeted the day after the ambush — security analysts see Mexico having little choice but to allow the FBI in.
"It’s a way to save face," Jorge Kawas, a security analyst in the city of Monterrey, said of inviting the FBI.
"Just look at how we’re using scarce resources to hunt (Central American) migrants in the south on behalf of Trump because of direct threats,” he added, referring to Mexico deploying a new militarized police force known as the National Guard to its southern states in response to Trump threatening to slap sanctions on Mexico unless migration through the country stopped.
Most murders in Mexico go unpunished. The rate of impunity in the state of Sonora, scene of the attack, hovers been 70% and 80%, according to online news organization Animal Politico.
"If you do not have some type of influence — whether financial or political — then you can usually forget about the law or the authorities working in your favor,” said Falko Ernst, senior Mexico analyst for the International Crisis Group.
Analysts interviewed by USA TODAY say high-profile murders and crimes involving foreigners from countries such as the United States have a higher chance of being brought to justice.
"Criminal groups know that messing with foreigners does usually mean you have to expect some type backlash," Ernst said. "The U.S. role adds a lot of pressure and I can imagine that some kind of result will be presented. Whether or not it’s to the satisfaction of the U.S. is another question."
After funerals for the women and children, families openly considered abandoning their longtime homes for the safety of the U.S. An 18-vehicle caravan carrying more than 100 members of the communities impacted by the Nov. 4 killings arrived in Arizona on Sunday.
“This community here will forever, ever be changed,” David Langford said Thursday during the funeral for wife Dawna Langford, 43. “One of the biggest things to our lives is the safety of our family, and I don’t feel safe. I haven’t for a few years here."
Kevin Johnson of USA TODAY and Rafael Carranza of The Arizona Republic contributed to this report.