MEXICO CITY — The women and their children were taking a drive along a familiar rural road in northern Mexico when the gunmen attacked, riddling the three-car convoy with bullets.

One woman was shot at close range in the chest. One child was shot in the back. Several others — among them 6-month-old twins — were burned beyond recognition when one of the vehicles caught fire.

When the shooting stopped, six children and three women were dead, all members of the LeBarón family, dual Mexican and American citizens who have lived for decades in a fundamentalist Mormon community near the border.

“When you know there are babies tied in a car seat that are burning because of some twisted evil that’s in this world, it’s just hard to cope with that,” Kenny LeBarón, a cousin of the women who were killed, said in a telephone interview.