With the crisis at the border reaching new levels of people. The government does not have the resources and are already overwhelmed, which has lead to problems with undocumented immigrants. Unfortunately, this has made them easier to get into the country as well.
There is data to show that immigrants account for pretty much 20% of federal prisons. These are people who are not U.S. citizens. Mexican nationals inface account for 12.1% of the prison population.