Sen. Chuck Grassley (R-IA) on Friday said that Monday's tragic bombing at the Boston Marathon was a reason not move to quickly to pass a bipartisan proposal for comprehensive immigration reform.

"Given the events of this week, it's important for us to understand the gaps and loopholes in our immigration system," Grassley told the Senate Judiciary Committee. "While we don't yet know the immigration status of people who terrorized the the communities in Massachusetts, when we find out, it will help shed light on the weaknesses of our system."

"How can individuals evade authority and plan such attacks on our soil? How can we beef up security checks on people who wish to enter the United States? How do we ensure that people who wish to do us harm are not eligible for benefits under the immigration laws, including this new bill before us?"

CBS News reported on Friday that 19-year-old Dzhokhar Tsarnaev, the man being hunted by police as a suspect in Monday's bombings, became a U.S. citizen on Sept. 11, 2012 after coming to the country on a tourist visa in April 2002. Before becoming a citizen, he sought asylum in September 2002 and gained lawful resident status in February 2007.

Dzhokhar Tsarnaev's 26-year-old brother, Tamerlan Tsarnaev, was killed in a firefight with police on Thursday night. His legal status was not immediately known.

Earlier this week, Rep. Steve King (R-IA) speculated that the bombings in Boston had been perpetrated by a “foreign national” and that Congress should proceed with caution on any immigration reform efforts. Rep. Louie Gohmert (R-TX) also warned that “radical Islamists” were “being trained to come in and act like Hispanics.”

Watch the video below from C-SPAN, broadcast April 19, 2013.

(h/t: Huffington Post)