FORT WORTH, Texas (Reuters) - A manhunt was underway on Thursday for a wealthy Texas teenager, described at trial as being afflicted with “affluenza,” who apparently fled to avoid violating a probation deal that kept him out of prison for killing four in a drunken-driving crash.

Ethan Couch, 18, is shown in this handout photo provided by the Tarrant County Sheriff's Department in Fort Worth, Texas, December 17, 2015. A manhunt was underway Thursday for Couch, a wealthy Texas teenager, described at trial as being afflicted with "affluenza", who apparently fled to avoid violating a probation deal that kept him out of prison for killing four in a drunken-driving crash. REUTERS/Tarrant County Sheriff's Dept/Handout via Reuters

The 18-year-old named by Tarrant County officials as Ethan Couch, and placed on the county’s most wanted list, missed his mandatory meeting with his probation officer, prompting a warrant for his apprehension to be issued on Dec. 11.

Couch’s name has been entered into a national fugitive database search, law enforcement officials said. The U.S. Marshals Service has joined local authorities in the search.

“He has no idea what he faces when he is found,” said Tarrant County Sheriff’s spokesman Terry Grisham.

The teen was sentenced to 10 years probation for intoxication manslaughter for the 2013 incident.

A psychologist who testified on the youth’s behalf at his trial claimed his condition of “affluenza” shielded him from responsibility for his actions but is not recognized as a diagnosis by the American Psychiatric Association.

Grisham said sheriff’s deputies tried to search the home he shared with mother and found the place cleaned out except for a pinball machine.

“This is a family that knows how to game the system and has done so from the start,” said Tarrant County Sheriff Dee Anderson.

Authorities said it is possible the teen and his mother fled the country. Sources close to the investigation said the teen’s father told law enforcement officials that the passports of the youth and his mother were missing.

The county launched an investigation this month after a video was made public that appeared to show the teen among a group at party where beer pong was being played.

The youth last met his probation officer around the time the video went public and did not return after that, according to sources familiar with the investigation.

“He got a big jump on us because he was gone before any of us knew that he was missing,” Anderson said.

The teen, who was 16 at the time of the deadly crash, had a blood-alcohol level of nearly three times the legal limit when he was speeding and lost control of his pickup truck.

The Tarrant County District Attorney’s office had initiated paperwork to transfer the youth from juvenile to adult supervision before the party video was released.