"LSU Sociology Professor Edward Shihadeh and Ph.D. candidate Raymond Barranco have published a study titled "Latino Employment and Black Violence: The Unintended Consequence of U.S. Immigration Policy," in the March 2010 issue of Social Forces, the field's preeminent journal.
The study confirms that Latino immigration and dominance of low skill jobs have displaced blacks from low-skill labor markets, which in turn led to more violence in urban black communities. According to their analysis, this is traceable to U.S. immigration policies over the last several decades."
Part of this is simply intuitive, especially if you live in California. There are curveballs in the research conclusions, however, which point to an unexpected linkage mechanism and unintended policy consequences. It doesn't really slot left or right. Which makes it pretty interesting as a starting point for debate.