In the interest of trying to protect the ability of undocumented immigrants to stay in America, in some cases their defenders go overboard in propping them up as contributors to society. One of those ways sites like Immigration Impact do this is to argue that illegal immigrants commit less crime than natural born citizens, if for no more moral reason than they feel the need to keep their heads down. One very notable area where this is not true, in many places, is murder.
National Review reported that in Arizona, a study by the Government Accountability Office found that illegal immigrants were roughly 28% more often convicted of homicide-related crimes than native born citizens. In California the likelihood was approximately 33% higher. If you think this is an attempt to characterize Mexican illegal immigrants in particular as more inclined to murder because all the states mentioned share a border with Mexico, it is not. In Texas, illegal immigrants were less likely than natural born to be convicted of murder. However, in New York, illegal immigrants were more than three times more likely to be convicted in homicide offenses. So this is hardly an issue limited to a specific region.