FORT WORTH, Texas (Reuters) - Lawyers for the Texas teenager who killed four people in the “affluenza” drunken-driving case and was captured in Mexico said on Tuesday they are investigating whether the 18-year-old chose to flee or was forced.

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Judge Timothy Menikos of Tarrant County juvenile court deferred a ruling on a move to transfer Ethan Couch’s case to adult court because his parents were not adequately notified about the proceedings.

Couch and his mother, Tonya Couch, 48, were captured in Puerto Vallarto, Mexico, last month after a manhunt of more than two weeks sparked by allegations the teen violated his probation in the 2013 drunken driving case.

“We are examining the facts ... to determine whether he was taken voluntarily or involuntarily to Mexico,” attorney Scott Brown told reporters.

Couch, held in a Mexico immigration detention center, may soon return to Texas, Brown said, adding that his Mexican lawyers are making moves to drop his fight against deportation.

A Mexican migration official said Couch’s transfer to the United States is not imminent.

“First, (Couch’s lawyers) have to withdraw the legal challenge ... and even then it would take another month,” said Ricardo Vera, the top migration official in Mexico’s central Jalisco state where Couch’s legal case is being handled.

Tarrant County prosecutors contended Couch is responsible for his own absence by fleeing to Mexico. His mother was returned to Texas and faces a third-degree felony charge, accused of helping her son flee, that could result in a 10-year prison sentence if she is convicted.

The teen’s parents are divorced, and his father was not present in court.

Couch was 16 when he was tried as a juvenile with a psychiatrist testifying the boy had “affluenza” and his family’s wealth had left him so spoiled that it impaired his judgment to tell right from wrong.

The affluenza diagnosis, not recognized by the American Psychiatric Association, was widely ridiculed.

A social media video emerged in December showing Couch at an alcohol-laden party. The party was likely a violation of the probation deal that kept him out of prison.

If Couch is found to have violated his probation, he could be held in adult detention for about four months.

Lawyers for Couch want the proceedings in Fort Worth stopped because he is not present. A new hearing date in the case was set for Feb. 19.