The search for the pair ended this week in Puerto Vallarta, a city of beaches and lavish resorts on Mexico's Pacific Coast, officials said at a news conference in Texas yesterday.
"As I said early on, there was a strong feeling, on many people's part, mine particularly, that they had fled the country once we found out they were missing," Tarrant County Sheriff Dee Anderson told reporters.
"Obviously, it was proven correct."
Anderson said investigators learned of "something that was almost akin to a going-away party". "Which, to us, meant that what we suspected had happened. That it was carefully planned and timed to get out of the country."
Couch failed to turn up for a routine probation meeting on December 10, according to the Tarrant County District Attorney's Office, and when an officer went to check on him, he was nowhere to be found.
Authorities issued a warrant for his arrest the following day.
The exact travel plans for mother and son remained somewhat unclear. US Marshal Rick Taylor said the duo would be treated as "undesirable" and would probably be expelled. "We still don't have a lot of details yet about his return, as well as the mother. We're still working through that with the Mexican Government."
The search reignited discussion of the teen's light sentence two years ago. In December 2013, Couch pleaded guilty in juvenile court to manslaughter and assault while intoxicated.
He had valium and a high level of alcohol in his blood and was speeding down a road on the outskirts of Fort Worth when he careened into a group of people fixing a broken-down car.
Although prosecutors pushed for a 20-year prison term, Couch was sentenced to 10 years of probation and no jail time.
During the trial, psychologist G. Dick Miller attributed Couch's reckless behaviour to "affluenza", saying that Couch had an unhealthy relationship with his millionaire parents, who didn't teach him that dangerous actions have consequences.
Instead, he "was taught we have the gold, we make the rules at the Couch household", Miller testified in court.
But during a hearing in February 2014, State District Judge Jean Boyd, who issued the sentence, told families involved that her decision had nothing to do with the "affluenza" argument, according to the Fort Worth Star-Telegram.
She said Couch, not his parents, was responsible for what happened.
When the mother and son return to the United States, officials will push to transfer his case from the juvenile system to the adult courts, Tarrant County District Attorney Sharen Wilson told reporters.
Tonya Couch is expected to be charged with hindering apprehension, Wilson said.
"I think that she deserves to be incarcerated," Wilson said.
Washington Post - Bloomberg
