A seven-month old baby has been found alive among the bodies of three and six children who were killed who were gunned down in northern Mexico.
Faith was stowed away by her mother Christina Langford Johnson in the back seat of their SUV.
Officials in the Central American country said she then got out of the vehicle, but she was shot and killed.
Two other mothers, twin babies and four other children were also gunned down in the attack. Five children were also wounded and were later flown to an Arizona hospital for treatment.
Faith was found inside the vehicle 11 hours later.
Mexican officials have said they believe the family were mistaken for members of a drug cartel by a rival gang as they travelled along a dirt road in Bavispe, Sonora, on their way to Chihuahua.
There had been a gunfight in the area earlier in the day, they added.
This was disputed by family member Max LeBaron, who said he believed they had been targetted.
"They are just trying to terrorise the community, the people who are here” he told CBS news. “They are just trying to run us out of our farms."
The group belonged to the LeBaron family - a breakaway Mormon community that settled in the hills and plains of northern Mexico decades ago when the Church of Jesus Christ of Latter-day Saints abandoned polygamy.
Drug-related violence has been raging in Mexico over the last two decades, with cartel gunmen increasingly unconcerned about killing children as collateral damage.
Around the ambush scene investigators found over 200 shell casings, mostly from assault rifles.
"Lately it's getting worse. This is a whole new level," said Taylor Langford, a relative of the dead who splits his time between the Mexican community and his home in the Salt Lake City suburb of Herriman, Utah.
The group have previously faced violence in the region.
In 2010, two members of the Chihuahua Mormon community, including one from the LeBaron family, were killed in apparent revenge after security forces tracked drug gang members.
Additional reporting by Associated Press