More Than 28,000 Mexican Citizens Housed in U.S. Federal Prisons

“An alien who illegally enters the U.S. and then commits a separate federal offense (e.g., assault) for which he is convicted in a federal court would typically serve his sentence for that offense (assault) and any other federal offenses in the Bureau's custody while simultaneously having an Immigration and Customs Enforcement (ICE) detainer awaiting him upon completion of his service of the sentence(s) in the Bureau's custody. After serving the sentence(s) in the Bureau's custody, ICE then determines whether to execute the detainer by detaining and deporting the individual,” the spokesman said.

“If ICE and other jurisdictions do not take an inmate into their custody by executing a detainer, then the Bureau does not have any legal authority to hold the inmate,” he added.

Long told PJM the Bureau of Prisons “does not track the total number of Mexican citizens in our custody who have committed illegal entry or illegal reentry offenses.”

He also said the bureau does not accept any transfers of inmates from Mexico unless they are U.S. citizens.

“Only U.S. citizens are transferred to the U.S. from Mexico under the treaty transfer program. Therefore, the only Mexican citizens that would have transferred to the U.S. would have been dual citizens and those numbers are not tracked,” he said.

According to Mexico's National Human Rights Commission, most of Mexico’s prisons are overcrowded.

“A report by the governmental commission said that of 130 state prisons inspected, 95 lack adequate guards and staff and 104 fail to adequately separate convicted inmates from people facing trial,” the AP reported in April. “The most shocking part of the report was the overcrowding found at 71 of the 130 penitentiaries.”

TIME magazine posted a video in 2009 from inside an overcrowded Mexican prison, describing the situation as an “exploding problem.”

Republican presidential nominee Donald Trump said during his campaign announcement speech that Mexico is sending some of its prisoners to the U.S. over the southwest border. The Federal Bureau of Prisons could not confirm or deny Trump’s claim because it does not track those statistics.

In December 2015, PJM asked Miguel Basáñez Ebergenyi, Mexican ambassador to the U.S. at the time, if Mexico has sent prisoners to the U.S. due to the overcrowding.

“No, no that is not the case,” he said. “That is part of the rhetoric in the political process.”

Ebergenyi said the Mexican prison population is “very low.”

“The prison population in Mexico is very low. The largest proportion of jailed people in the world is in the U.S., OK? The overcrowding of prisoners over there is because there are not enough resources,” he said.