The Mexican government on Sunday invited the FBI to send investigators to help in the investigation of the murder of nine U.S. citizens—six children, including 8-month-old twins, and three women—living in a Mormon community about 100 miles south of the border in the state of Sonora.

According to Reuters, Mexico’s Foreign Ministry said in a statement, "The Mexican government reiterates its commitment to investigate the facts, in order to ... offer justice to the affected families."

Shortly after the killing of the Americans living in Mexico, the FBI offered assistance, but it took nearly a week for the Mexican government to take the agency up on that offer.