WATCH: Eye-popping illegal immigration stat prompts senator's demand to 'redouble' deportations

The hearing, chaired by Rep. Thomas McClintock, R-Calif., examined several examples of allegedly lax prosecutions by Descano involving illegal immigrants with prior rap sheets - including a Sierra Leone national accused of murdering a young woman at a bus stop on U.S. 1.

"The first step would be to give up on the mass deportation fantasy," Bier said.

While Bier later added that he believes noncitizens who harm Americans should be deported, his earlier statement drew the attention of several immigration hawks, including Sen. Mike Lee, R-Utah.

Lee borrowed Bier's logic to prove immigration hardliners' point that mass deportation is the right solution:

"On the contrary: 20% of a wealthy DC suburb being illegal immigrants means we should redouble our efforts to deport them all," Lee said.

Bier responded to Lee's comments in a lengthy statement to Fox News Digital, arguing the Utah Republican failed to explain why mass deportation would benefit Americans in Fairfax County.

"What was the senator's explanation for [his] statement? The senator never says why it would benefit the country to harm Fairfax County and the Americans who live there, so there's nothing to rebut," Bier said.

"The senator is wrong to characterize the 20% as all illegal immigrants since half of them are just people who live with illegal immigrants, which is precisely my point."

"Mass deportation would harm those Americans and many others by ripping them away from their spouses, parents, children, friends, family, employees, employers, customers, nurses, nannies, and teachers," the immigration expert added.

Bier said mass deportation becomes more expensive and impractical as the population of illegal immigrants grows, meaning continuing on the current course will harm Americans.

"I would ask the senator: how many Americans would have to be hurt by mass deportation before he would reconsider his views?"

"The stories of the victims and facts speak for themselves. The sanctuary politicians of Fairfax County have blood on their hands," the spokesperson said.

"We have politicians who want to protect the criminals, President Trump is still protecting all of our neighborhoods," Mullin said.