Lafe Langford’s face is frozen in disbelief after nine of his relatives were killed.

It’s been two days since gunmen ambushed a convoy of mothers and children in northern Mexico, killing three women and six of their children.

Now, he’s learning that two of the children who survived the attack walked for hours trying to get help.

“A lot of details are still surfacing,” Langford told CNN’s “New Day” on Wednesday. “We’ve been learning a lot of facts and truths and incredible stories from survivors as they’re recovering in the hospitals.”

The nine slain victims, who had dual US-Mexican citizenship, were members of a Mormon community that appeared to be fundamentalist. The community is separate from the mainstream Church of Jesus Christ of Latter-day Saints.

On Monday, the three mothers were driving in a convoy for protection as they headed to see other family members.

“All of a sudden, bullets just rained from above, from on top of a hill, down on top of them,” Langford said. “The mothers were dead. There were seven wounded children that were alive.”

According to the young survivors, “once the firing stopped, these men came off the mountain and pulled all these kids that were still alive,” Langford said.

“They basically told them to get out of here. So they immediately started walking toward home,” taking turns carrying a young boy who was severely wounded.

He marveled at the “heroic actions” of the children who tried to help each other in the remote mountainous area near the Sonora-Chihuahua border.

It’s difficult to process “the loneliness that they felt in those mountains for hours and hours, all shot up and wounded, carrying each other in their arms,” Langford said.

Devin Blake Langford, 13, watched his mother and two brothers die.

“What Devin has told us is that one of the three vehicles was shot up and then set ablaze,” Lafe Langford said.

Devin hid six of his siblings in bushes and covered them with branches to “keep them safe while he sought help,” another relative, Kendra Lee Miller, wrote on Facebook.

As nightfall loomed, 9-year-old McKenzie Langford — who was shot in the wrist — grew worried about Devin and said, “I gotta go find him,” Lafe Langford said.

“She had a bullet through her wrist, but nevertheless, she was probably in the best shape to walk at that point. And so away she went,” Langford said.

“And we found her by her little footprints. She took the wrong road. Six hours later, and we saw that her footprints had a shoe, and then a bare little foot because she had to take her shoes off and her feet were just swollen and covered in blisters when they found her at 9:30 at night.”

But McKenzie didn’t complain about her injuries.

“The first thing that came out of her mouth when she saw her uncles was, ‘We have to go back. We have to go back. My siblings, my brothers and sisters are dying. They’re bleeding, they’re shot. We have to go rescue them.’ And that’s all she cared about,” Langford said.

“What they went through, what they experienced — we don’t have the capacity just to imagine what these children went through.”