Authorities said a Texas teenager serving probation for killing four people in a drunken-driving wreck after invoking an "affluenza" defense was in custody in Mexico, weeks after he and his mother disappeared.

Mexico's Jalisco state prosecutors' office said in a statement that its agents had been working with American authorities via the U.S. Consulate in Guadalajara since Dec. 26 to track down and capture 18-year-old Ethan Couch and his mother, Tonya Couch. The office said the two were located and detained Monday evening in a beachside neighborhood of the Pacific Coast resort city of Puerto Vallarta.

After their detention, they were handed over to Mexican immigration authorities for deportation, the statement said.

During the sentencing phase of Couch's trial, a defense expert argued that Couch's 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 widespread ridicule.

Couch and his mother were found in a dowdy section of Puerto Vallarta's old town, far from the glitzy resorts, golf courses and high-rise hotels of the city's newer section.

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