“Even before the migration to Mexico had begun, Apostle Brigham Young, Jr. had warned members of the Church living in Arizona ‘that the blood of Cain was more predominant in these Mexicans than that of Israel.’ For this reason he ‘condemned the mixing’ of Mormons with ‘outsiders.’”

B. Carmon Hardy, Pacific Historical Review – Volume 34, “Cultural ‘Encystment’ as a Cause of the Exodus from Mexico in 1912″ (1965), 447.