The three American women and six children killed in northern Mexico were victims of a territorial dispute between an arm of the Sinaloa Cartel and a rival gang, and may have been used to lure one side into a firefight, officials say.
Members of breakaway Mormon communities that settled in Mexico decades ago, the three families were ambushed on Monday morning as they drove along a dirt track in Sonora state.
Their deaths have led to US President Donald Trump urging Mexico and the United States to "wage war' together on the drug cartels.
Emerging accounts of the slayings detailed the heroism of a surviving boy who walked for miles to get help for his siblings, and heavy gun battles in the remote hill area that lasted for hours into the night after the attack.
"We were deliberately targeted, used as bait to lure one cartel against another," said Lafe Langford, a cousin of some of the victims, who grew up in the same Mormon village.
Hitmen opened fire on the three mothers and 14 children travelling from a village in Sonora to meet with relatives in neighbouring Chihuahua state and Phoenix, Arizona.
When the killers struck, the families were spread out along a 20 kilometre stretch of road near the border of the two states, according to Mexican authorities and the families.
As bullets began to pummel the first car, Christina Marie Langford Johnson stepped out waving her arms to show that they were not gang members, according to a family statement based on reports from the surviving children.
Christina was shot dead. Her baby, Faith, survived the attack in a child seat that her mother appeared to have placed on the floor before she got out.
Gunfire also ripped into a second vehicle carrying Dawna Langford and nine children, some two kilometres behind, authorities said. Dawna and two sons were killed.
Her uninjured 13-year-old son Devin hid six surviving siblings nearby and walked for 23km to find a rescue party.
Reuters video of the stricken vehicle showed more than a dozen bullet holes in the roof and sides of the vehicle.
A third car, 18km behind, was shot up and burst into flames, killing Rhonita Miller and her four children.
Some hours earlier, the La Linea arm of the Chihuahua-based Juarez Cartel sent gunmen to defend the state border area, after attacks in a nearby town by the Los Salazar faction of the rival Sinaloa Cartel, a top Mexican general told reporters.
The Juarez Cartel wanted the Sinaloa Cartel off its turf, General Homero Mendoza said.
While no official explanation has been given for the killings, Mendoza and other officials say the gang may have mistaken the families' SUVs for those of its rival.
Relatives of the victims rejected the mistaken identity theory, arguing that shell casings and personal belongings found near the torched car suggest the attackers came close and made sure everybody was dead before igniting the vehicle.
The Mexican government has countered Trump's call by urging Washington to help stop the flow of American weapons south of the border, and Security Minister Alfonso Durazo said Remington shell casings of US origin were found at the crime scene.
© RAW 2019