(CNN) Nahoma Jensen De LeBaron, the cousin of one of the nine victims of Monday's massacre in the mountains of Mexico, said the cartels they suspect of the attack exist due to the demand for drugs in the United States.

"I believe the United States is the reason why Mexico has drug cartels, because they're the biggest consumers," LeBaron told CNN en Espanol on Friday before families buried more of the dead.

She said the problem wasn't all Americans but there were enough people buying drugs to keep organized crime in Mexico busy.

LeBaron said US citizens need to step up and do things to lessen the demand for drugs that are destroying families. But she also pointed to the Mexican government, saying the justice system there doesn't do enough to bring the cartels to justice.

Six children and three women were shot and killed Monday on a remote dirt road in Sonora, an attack relatives and other members of the community think was targeted at the three-vehicle convoy.

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