This scholarly study looked at the effects of immigrants on cities. They conclude: "ontrolling for the demographic characteristics of the cities, recent immigrants appear to have no effect on crime rates. In explaining changes in a city's crime rate over time, the flow of immigrants again has no effect."
A scholarly article. "Data uniformly show no association between immigrant population size and increased violent crime. However, there appears to be a small but significant association between undocumented immigrant populations and drug-related arrests."
A scholarly paper. “If we adopt a more inclusive definition of the criminal class, including all convicted of a felony regardless of imprisonment, these numbers increase to 19.8 million persons, representing 8.6 percent of the adult population.” (p. 12).