Tarrant County Sheriff Dee Anderson said 18-year-old Ethan Couch - who was on juvenile probation after killing four people in a drunken driving wreck - and his mother had prepared to be gone a while, even dyeing Couch's blond hair black, before being detained Monday in the Pacific Coast city of Puerto Vallarta.
"They had planned to disappear. They even had something that was almost akin to a going-away party before leaving town," Anderson said. He would not give details about the event, including how many people attended.
During the sentencing phase of Couch's trial, a defense expert argued that his wealthy parents coddled him into a sense of irresponsibility - a condition the expert termed "affluenza." The condition is not recognized as a medical diagnosis by the American Psychiatric Association, and its invocation drew ridicule.
Couch disappeared as authorities investigated whether he had violated the terms of his probation.
Anderson said Couch and his mother, Tonya Couch, apparently crossed the border in her pickup and drove to Puerto Vallarta. It was not clear whether they had any accomplices.
No immediate charges were planned for others who may have known about or assisted with the flight plan, Anderson said. He said authorities have no evidence that Ethan Couch's father, who owns a sheet metal factory in North Texas, was involved.
Jalisco state prosecutor Eduardo Almaguer Ramirez said US authorities knew the mother and son were in Puerto Vallarta because of a phone call to Domino's Pizza.
A US Marshals Service agent tipped authorities in Mexico to the location of the phone on Monday, according to a police report issued by the Jalisco state prosecutors' office. The phone had been used to order pizza for a room at a condominium complex in the beach resort city.
When agents went to the condo, the Couches had already moved on, but a tourism operator pointed agents to the mother and son's new home at an apartment in Puerto Vallarta's old town. Agents set up a surveillance operation in the area and found the Couches that night.
The police report says they claimed to be carrying no identification and gave inconsistent stories about their names.
They were taken into custody and handed over to Immigration officials.
Anderson noted that Ethan Couch's hair was "markedly different." A photo distributed by the Jalisco state prosecutors' office shows him in detention with his blond hair dyed black and his normally blondish beard now brown.
The sheriff has said he believes the two fled in late November after a video surfaced that appears to show Couch at a party where people were drinking. If found to be drinking, Couch's probation could be revoked and he could face up to four months in jail. Once returned to Texas, Couch will be held in a Tarrant County facility until a probation violation hearing next month.
Anderson said an arrest warrant was being issued for Tonya Couch on charges of hindering an apprehension, a third-degree felony that carries a sentence of two to 10 years in prison.
Tarrant County District Attorney Sharen Wilson said she plans to ask a judge to transfer Ethan Couch's case to adult court.
Couch would then face up to 120 days in an adult jail, followed by 10 years' probation. If he violates probation, he could face up to 10 years in prison per death, Wilson said.
If the judge declines to transfer Couch to adult court, Wilson will ask that his probation be revoked, in which case he could be held in a juvenile facility until his sentence expires when he turns 19 next April.
Couch's attorneys, Scott Brown and Reagan Wynn, said they won't comment until they speak with him, which likely won't happen before Couch reaches the US.
Ricardo Ariel Vera, the representative of Mexico's immigration institute in Jalisco state, said the mother and son were being held at immigration offices in Guadalajara and would be returned to the United States aboard a commercial flight to Houston.
"They are going to be sent back to their country, given that they were in Mexico improperly," Ariel Vera said. "They would have had to enter, for example, as tourists, but they entered without registering."
He initially said that would happen on Tuesday; however, another immigration official who is not allowed to be quoted by name told The Associated Press that there were no seats available on commercial flights and the return would be Wednesday.
Couch was driving drunk and speeding on a road south of Fort Worth in June 2013 when he crashed into a disabled SUV off to the side, killing four people and injuring several others, including passengers in his pickup truck.
He pleaded guilty to four counts of intoxication manslaughter and two counts of intoxication assault causing serious bodily injury. A judge sentenced him in juvenile court to 10 years' probation and a stint in a rehabilitation center.
Authorities had begun searching for Couch and his mother after he missed a mandatory appointment with his probation officer on December 10.