It takes three DUIs to deport a legal immigrant. Why?

LILBURN, Ga. - Even if a foreign-born person is in this country legally, they can still be deported if they break the law.

But there's one law they're allowed to break multiple times and still stay here.

Drunk driving.

The FOX 5 I-Team discovered dozens of cases in Gwinnett and Cobb where immigrants were only referred to immigration authorities after their third DUI conviction.

"They shouldn't be here," agreed Atlanta immigration attorney Charles Kuck. "The reality is if you've been convicted more than once for a DUI, you should be gone."

The rule for immigrants here illegally is a lot tougher. As long as they are convicted of drunk driving and not just charged, they can be deported after just one DUI. But for someone here legally, like on a work permit or green card, they usually can't be kicked out unless they commit a felony. And that takes three DUIs.

Jose Lara-Rostro got the hat trick in 2015.

Lilburn police found the Mexican-born legal resident passed out at a traffic light. When they tried to wake him, he took off, running several red lights.

"He's all over the road," one of the officers calls back to dispatch. "If he doesn't stop he's going to kill somebody."

Luckily, Lara-Rostro did not kill anyone on this crazy night. He crashed into a ditch and was carried away on a stretcher. Last August the Mexican-born legal resident would plead guilty to his third DUI. Only then could he be deported.

Our analysis of immigrant arrests in Cobb and Gwinnett counties found lots of multiple DUI offenders.

Adan Herrera-Mata... pled guilty in 2009, 2012 and 2013 in Gwinnett County.

Phat Ngu Lam - guilty in 2009, 2012 and 2015.

Jose Chavez... guilty in 2014... 2015... and later tested positive for cocaine.

Because immigration records are often private and public records for these cases contain limited information, it's impossible to know whether these men were here legally or were eventually deported yet came back to drive drunk again.

"If you're a guest in our country, why would you give someone more than once chance at killing somebody?" asked Gwinnett County sheriff Butch Conway. He thinks not matter what an immigrant's legal status, the rule should be one DUI and you're gone.

"The dangers of drunk driving I think are underestimated in a lot of the immigrant populations," explained Kuck.

Because it's one of those minor crimes that can lead to so much tragedy. Like what happened on a two-lane Hart County road the day after Thanksgiving, 2014.

"I was putting up some Christmas decorations and I was trying to call her to see if she knew where it was," remembered Louise Cannon. "But she never answered."

That's because her daughter-in-law Kathryn, son Russell and five-year-old granddaughter Rose Marie had been killed by a drunk driver as they headed to Hartwell to go Christmas tree shopping.

Before they left home, someone had given the little girl a dollar to spend.

"And she died with that dollar in her hand," Ms. Cannon explained. "That's the most heartbreaking thing."

The man who would plead guilty to vehicular homicide was Guatamalean native Marco Hernandez Ramirez. He was in this country illegally, coming back even after being deported once before. On the day of the crash prosecutors said he drank 24 beers before getting into a work van and weaving his way toward Franklin County. His blood alcohol level -  point 27, more than three times the legal limit.

"DUI is a very serious offense because it turns our roadways into war zones," lamented district attorney Parks White. "We're a nation of immigrants certainly. But if we're not a nation of laws then we have nothing but chaos."

But under this nation's current laws, if Ramirez had been a legal immigrant, and driven drunk without killing someone, he could not be deported until he was caught three times.

He got his wish, just not the address he wanted. Ramirez will now get to stay on U.S. soil for perhaps the next 40 years. In prison.

"He gave them the death sentence," Ms. Cannon stressed. "And the rest of the family, we got a life sentence because of the heartache we'll always have to live with."

Think it’s easy to find out whether someone’s deported? It’s not. Read Randy’s first-person account by clicking here.

RELATED: Jail records reveal immigrants not deported after minor crimes later commit worse ones