Since 2000, 16 of the last 34 mass shootings, 47%, that did not revolve around a family dispute, targeted assassinations of law enforcement or those that occurred on an Indian reservation, were committed by first and second-generation immigrants. The Federal Bureau of Investigation (FBI) classifies mass shootings as shootings in which four or more people are shot and killed over a brief period in a particular area and when the shooter is not doing so in the commission of another crime.
The immigration policy in place prior to the 1965 Hart-Cellar Act pushed by Ted Kennedy, would have ensured that the vast majority of these foreign nationals would have never been imported to the United States if any at all.
Salvador Tapia is an immigrant from Mexico. In 2003, Tapia decided to return to his former workplace in Chicago, Illinois, and shoot several people in the Windy City Core Supply warehouse. This massacre left six people dead.