Republican senators are launching an investigation into how a Mexican illegal immigrant, and a former recipient of the Obama-era program that shielded immigrants from deportation, was never deported despite a history of criminal behavior that allegedly culminated in the deaths of four motorcyclists in July.

Sens. Chuck Grassley, R-Iowa, Kelly Loeffler, R-Ga., Josh Hawley, R-Mo., Thom Tillis, R-NC., Ted Cruz, R-Texas, Tom Cotton, R-Ark., Joni Ernst, R-Iowa, Marsha Blackburn, R-Tenn., and Mike Lee, R-Utah, wrote to U.S. Citizenship and Immigration Service (USCIS) and Immigration and Customs Enforcement (ICE) demanding answers about Ivan Robles Navejas.

ICE OPERATIONS NAB MORE THAN 2,000 ILLEGAL IMMIGRANTS, MANY WITH CRIMINAL CHARGES, CONVICTIONS

“We are concerned by reports that this individual was in the United States unlawfully and, despite having been encountered by law enforcement and immigration officials on previous occasions, no action was taken to ensure that this criminal alien was removed from our communities,” the senators wrote.

Navejas is accused of killing four members of the Thin Blue Line Law Enforcement Motorcycle Club in July when, according to local outlets, the car he was driving traveled across the center line and hit the motorcycles traveling in the opposite direction. Navejas is charged with DWI, multiple counts of intoxication manslaughter and also multiple counts of intoxication assault, according to KHOU11.

The Republican senators, in their letter, note that it is not the first charges Navejas has faced.

“He has faced previous charges including resisting arrest in 2013, driving while intoxicated in 2016, and, most concerning of all, aggravated assault in 2018,” they wrote. “We are disturbed by the fact that, despite these egregious charges, Mr. Navejas has been permitted to continue residing in the United States, further endangering our citizens.”

Navejas reportedly came to the country illegally but was a recipient of the Deferred Action for Childhood Arrivals (DACA) program which shielded recipients from deportation. President Obama signed the order in 2012, and President Trump campaigned on overturning the order -- although he was blocked this summer by the Supreme Court.

The lawmakers say that Navejas was granted DACA deferred status in 2013, the same year he was charged with resisting arrest. Although his DACA status later expired in 2015, he was later allowed to stay in the country despite drunk driving charges because such offenses were not considered enough to make him a deportation priority.

ILLEGAL IMMIGRANT RELEASED IN NYC AFTER ARREST FOR WEAPONS CHARGES, NOW ARRESTED ON GANG-RELATED CHARGES

“The guidance further allowed for the use of discretion when taking enforcement action against those unlawfully present in the United States. ICE used that discretion in this case by choosing not to take enforcement action,” the lawmakers said.

He is believed to have later received lawful permanent residence status, which would prevent his removal when he was charged with aggravated assault in an incident in which he is accused of biting off a portion of a man’s ear. That conditional residency expired in Jan. 2019.

CLICK HERE TO GET THE FOX NEWS APP

“As is so often the case, this tragedy was completely avoidable had this nation’s immigration laws been enforced as they should have been during the Obama administration,” the lawmakers wrote.

The lawmakers are requesting his immigration files and applications, as well as his encounters with law enforcement and the reason for which his DACA status expired. Also, they ask whether ICE put out a detainer for his removal.