A teenage fugitive who's known for using an "affluenza" defense at his trial for causing a deadly drunken car crash has won an injunction to stay in Mexico, but legal experts say any argument that his human rights have been infringed upon likely won't hold up.

Ethan Couch, 18, and his mother, Tonya Couch, were taken into custody last week in the Pacific resort city of Puerto Vallarta, where authorities believe they fled in November as Texas prosecutors investigated whether he had violated the terms of his probation.

Ethan Couch was driving drunk and speeding near Fort Worth in June 2013 when he crashed into a disabled SUV, killing four people and injuring several others, including passengers in his pickup truck. He pleaded guilty in juvenile court to four counts of intoxication manslaughter and two counts of intoxication assault causing serious bodily injury and was sentenced to 10 years' probation.

The Couches fled shortly after a video surfaced in November that appears to show Ethan Couch at a party where people were drinking.

Couch is being held at an immigration detention center in Mexico City. His mother, meanwhile, awaits transfer to Texas from Los Angeles, where on Tuesday she waived her right to an extradition hearing.

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Q: WHY WOULD ETHAN COUCH FLEE TO MEXICO?

A: Because human rights are protected in the Mexican constitution, American felons fleeing capital punishment or lengthy prison terms have treated Mexico as a refuge, said Washington, D.C.-based attorney Bruce Zagaris.

In 2005, though, the Mexican Supreme Court broke with legal tradition by agreeing to allow the extradition of criminal suspects who face life sentences abroad. Judges have refused extradition requests from the U.S. when the suspect faces cruel and unusual punishment, including the death penalty.

Zagaris said it's unlikely that such protections would be offered to Ethan Couch, though.

"Because of his money and power, it's hard for Ethan Couch to allege, as you normally would if you were a potential victim of human rights violations, that he's going to be subject to unusual and cruel treatment," he said.

It is unclear whether Mexico was the Couches' final destination, or what punishment they anticipated Ethan Couch would receive for violating his probation.

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Q: WHAT COULD ETHAN COUCH GAIN BY DELAYING HIS DEPORTATION?

A: A federal judge could rule that he stays in Mexico on a permanent basis under court protection, but such a judgment is unlikely, legal experts said. While the judge considers his appeal, Couch will remain in the immigration detention center, which "buys time to prepare his defense" in the U.S., said Javier Lopez de Obeso, a San Antonio attorney licensed to practice in Mexico who is not involved with the case.

Most likely, Lopez says, Couch will be deported back to Texas. Even if the judge rules in his favor, Mexican authorities are not likely to reject an extradition request from the U.S.

Tarrant County District Attorney Sharen Wilson has said she plans to ask a judge to transfer his case to adult court, where Couch could get up to 120 days in an adult jail, followed by 10 years of probation. If he violates probation again, he could face up to 10 years in prison per death, Wilson said.

Tarrant County district attorney spokeswoman Samantha Jordan said delaying his return won't affect his probation or prosecutors' plans to request a transfer. "If the motion to transfer is not settled before his return there would be a hearing immediately after he's back to transfer, and he would still owe the balance of time on his probation term," she said.

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Q: WHAT'S NEXT?

A: Ethan Couch won a delay in deportation last week, a ruling that could lead to a drawn-out court process if a Mexican judge decides Couch has grounds to challenge his deportation based on arguments that kicking him out of Mexico would violate his rights.

Such cases can take anywhere from two weeks to several months, depending on the priorities of the local courts and the actions of defense attorneys, said Richard Hunter, chief deputy for the U.S. Marshals Service in South Texas.

His lawyer in Mexico, Fernando Benitez, said he planned to meet with Couch earlier this week to decide whether to drop the deportation fight, but he has not commented on his legal strategy going forward.