Illegal immigrants convicted of various crimes committed more than 100 murders in four years after they were released from prison and not deported by the Obama administration, according to a new report.

The Miami Herald cites a Senate Judiciary Committee document dating back to 2015, which discusses the recidivism rate among people living in the United States illegally.

The letter states that at least 121 homicides between 2010 and 2014 "could have been avoided" if the Immigrations and Customs Enforcement (ICE) agency deported convicted immigrants rather than release them.

"This disturbing fact follows ICE's admission that, of the 36,007 criminal aliens it released from ICE custody in Fiscal Year 2013, 1,000 have been re-convicted of additional crimes in the short time since their release," the June 12, 2015 letter reads.

President Donald Trump has vowed to crack down on illegal immigration. He also instituted a temporary immigration ban from seven countries with a terror presence and halted America's refugee program from certain countries, although those directives have since become inactive as the court system rules on them.

The Herald reports that the majority of the illegal immigrant convicts in question came from countries that generally do not take back people who are deportable. Coupled with a Supreme Court ruling from 15 years ago that says the U.S. cannot imprison a deportable foreign national for more than six months, illegal immigrant convicts are often allowed to stay in the U.S.

The Trump administration has promised to strip federal grant money to cities and other municipalities that do not enforce federal immigration law, known as sanctuary cities.

"Should places in this country that ignore the laws of this country when it comes to immigration receive federal money into their communities? And the answer to me is no," White House chief of staff Reince Priebus said last month.