Plans to return a teen fugitive to the United States from Mexico hit a speed bump after Mexican officials announced on Wednesday that the Texas native had won a temporary stay against deportation.

Ethan Couch, 18, and his mother, Tonya Couch, were being held at immigration offices in Guadalajara, authorities said.

Couch was sentenced to 10 years of probation for killing four people while driving drunk in 2013. During the sentencing phase of Couch's trial in Texas, 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.

A U.S. Marshals Service agent tipped local authorities off Monday to the location of Couch and his mother, according to a police report issued by the Jalisco state prosecutors' office. Couch disappeared as authorities investigated whether he had violated the terms of his probation.

Mexican police say the fugitive “affluenza” teenager and his mother spent three days in a rented condo at a resort development in Puerto Vallarta before finding an apartment in a less glitzy area where they were found by police.

On Monday evening, detectives approached two people on a street matching the Couches' description. The police report said they showed an “evasive attitude,” gave inconsistent stories about their names and failed to provide proof of their legal migratory status in Mexico.

“They were confusing about their names and mentioned they had no identification and no immigration documents,” the report said.

They were taken into custody and handed over to immigration officials.

Tarrant County Sheriff Dee Anderson said Tuesday that the Couches had prepared to be gone a while, even dyeing Couch's blond hair black.

“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.

Anderson said Couch and his mother 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 Couch's father, who owns a sheet metal factory in North Texas, was involved.

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. Authorities had begun searching for the pair after Ethan Couch missed a mandatory appointment with his probation officer on Dec. 10.

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 Jan. 19.

Tarrant County District Attorney Sharen Wilson said that at the hearing 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-year 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.

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.

Al Jazeera and wire services