(CNN) After his mother was shot in an ambush near the US-Mexico border, a 13-year-old boy hid his siblings and walked for about six hours to get help, his family said.

Devin Blake Langford hid six of his siblings in bushes and covered them with branches to "keep them safe while he sought help," relative Kendra Lee Miller wrote on a Facebook post Tuesday.

The boy's mother, Dawna Ray Langford, was driving one of three of vehicles that were part of an apparent ambush that left nine women and children dead in Mexico's Sonora state on Monday.

Dawna Langford and the two other mothers were driving each of the three vehicles. They were killed along with four small children and two infants, family member Alex LeBaron said.

After seeing his mother and two brothers die, Devin walked about 14 miles to La Mora and relayed the "first news anyone had heard" of the attack, Miller said.

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