One of the many tropes used against immigrants today is that rising immigration brings rising crime rates.
A recent report by the Public Policy Institute of California, a nonpartisan research group, asked the question: Are the foreign-born more likely than the U.S.-born to commit crimes?
The answer? "No"
The heart of the matter is found in this quote by the authors of the report: "In California, as in the rest of the nation, immigrants ... have extremely low rates of criminal activity." Available data "suggest that long-standing fears of immigration as a threat to public safety are unjustified."
The report also noted that native-born men are incarcerated at a rate 2.5 times higher than foreign-born men. Moreover, the research indicates that "limiting immigration, requiring higher education levels to obtain visas, or spending more money to increase penalties against criminal immigrants will have little impact on public safety."
The study did not differentiate between legal and illegal immigrants.
Here is the full report: "Crime, Corrections, and California: What Does Immigration Have to Do with It?"