NASHVILLE, Tenn. -- As the crackdown on illegal immigrants continues, research uncovered some surprising numbers.

Video: Records Find Large Percentage Of Foreign-Born Inmates Illegal | Special Section: Immigration In America

The city of Nashville is in the process of deporting more than 1,000 illegal immigrants, and all of them have committed a crime in Davidson County.

Officials said there was always suspicion as to how many of the foreign-born criminals were illegal, but unless they committed a serious crime, no one checked into it.

But one case changed how closely checks are maintained.

When Gustavo Garcia Reyes was convicted of killing Sean and Donna Wilson in a drunk-driving crash, the cases of all the immigrants in the Davidson County Jail were opened.

“This person had been in our jail 14 times and the federal government didn’t tell us he was here illegally until he killed two people and they said, ‘We don’t have the time and resources to look into someone’s status until they commit an aggravated felony offense.’ Well it’s too late. It’s too late to help our community if you’re going to wait until they’ve killed people,” said Davidson County Sheriff Daron Hall.

The Wilsons’ daughter, Heather Steffek, added an angry voice to the argument.

“'Oh now we’ve finally got him (Reyes), oh, we’ll do something about him now that he’s killed someone.’ Well, you know, what if they’d done something on the first arrest? What if they would have said, ‘Hey, wait a minute, this guy is illegal, maybe we should hold him and figure out where he needs to be and not in our country,’” she said.

Since the Wilsons’ case, all convicted and alleged offenders are more closely scrutinized.

In only three months, the immigration enforcement program in Davidson County has begun deporting more than 1,000 illegal immigrant criminals.

According to records, 76 percent of foreign-born jail inmates are illegal.

One of the arguments that has been made against the deportation program is the assumption that those deported will come back illegally again.

“It may happen, (but) I do not believe at all that people would want to run right back to Nashville after having been sent through a series of processes, and breaking up of families in some cases, to deport you only to come back here and continue to commit crime and continue to live in our country illegally in Nashville. I think more likely is that people would leave Nashville to move to communities where it’s not being enforced,” Hall said.