Authorities in Mexico have caught Ethan Couch, the teen who received only probation after killing four people while driving drunk in 2013. (Gillian Brockell/The Washington Post)

Amid a nationwide manhunt for a Texas teen — infamous for the “affluenza” defense that helped him avoid prison time following a fatal drunk-driving crash — authorities now say the 18-year-old’s mother has been listed as a missing person.

Ethan Couch's mother, Tonya Couch, has been listed as a missing person. (Tarrant County Sheriff's Office) Ethan Couch’s mother, Tonya, has been listed as a missing person. (Tarrant County Sheriff’s Office)

For the past week, U.S. marshals have been searching for Ethan Couch, who is wanted for a possible probation violation in a 2013 vehicular manslaughter case.

Authorities said in a statement Monday that his mother, Tonya Couch, 48, has been named a missing person “in all relevant national databases” and may be traveling with her son in a pickup truck.

“He continues to believe the law doesn’t apply to him, which is how he was raised,” Tarrant County Sheriff Dee Anderson said during a news conference, according to the Dallas Morning News. “If he has enough money, he can get out of it.”

The mother of the teenager whose drunk driving trial included a defense witness saying that he was afflicted with "affluenza" has been listed as a missing person, making her part of the investigation into his probation violation, Texas officials said on Dec. 21. (Reuters)

Authorities have enlisted the public’s help in finding Tonya Couch’s pickup truck — a black 2011 Ford F-150 Harley Davidson edition. Authorities said it has 23-inch chrome wheels, “crease-like damage to the passenger side real panel” and a Texas license plate: BC50945.

[Authorities fear ‘affluenza’ teen may have fled the country but vow: ‘We’re going to find you’]

In June 2013, Couch was driving his friends down a two-lane road in Fort Worth, about 30 miles from Dallas, and had a blood-alcohol level three times the legal limit and Valium in his system, authorities said. He crashed into passersby who had stopped to help a stranded motorist.

Four people were killed.

Couch, who was 16 at the time of the fatal crash, pleaded guilty to manslaughter and assault while intoxicated, according to the Associated Press.

It was his trial that thrust him into the national spotlight.

His attorneys argued that he was a spoiled rich kid whose privilege prevented him from distinguishing right from wrong. Indeed, his family is reported to be worth millions, thanks in part to a booming sheet metal business. It’s their success — and the way they have handled it — that contributed to Couch’s reckless behavior, his attorneys argued.

They recommended a lesser sentence — and won.

Couch was sentenced to drug-and-alcohol-free probation for 10 years as well as time in a rehabilitation center. But the term was tricky. Under Texas law, because Couch was younger than 17 when he committed the crime, his case would remain in juvenile court until his 19th birthday — and then his sentence would disappear, said Sam Jordan, a spokeswoman for the Tarrant County District Attorney’s Office.

The prosecutor’s office filed a motion last month to have the case moved from juvenile court to adult court when he turns 19 next year, so that he would have to serve out his sentence.

“We think he should have been in the adult system already,” Jordan said, “so we applied to have the case moved, meaning he would have to serve the remaining eight years of his probation.”

A judge is expected to rule on the request next year, Jordan said.

“Unfortunately, it’s not something that can be done in absentia,” she said. “He has to be at the hearing.”

Terry Grisham, a spokesman for the Tarrant County Sheriff’s Office, said that until Couch has been found, the motion to move his case cannot proceed.

“As long as he is on the run, he will be a juvenile forever,” he said.

Local authorities started searching for Couch when he failed to show up to a Dec. 10 probation meeting, according to the prosecutor’s office.

About the same time, a video emerged on social media showing a young man who resembles Couch engaging in a beer-pong game — which could be a violation of his probation. “We’ve certainly had witnesses who said it was him,” Jordan said. However, she said, “there’s no DNA for video.”

The U.S. Marshals Service joined the investigation and, over the weekend, put up a $5,000 reward for information that leads to Couch’s whereabouts or arrest.

(Tarrant County Sheriff's Office) Tonya Couch’s truck. (Tarrant County Sheriff’s Office)

Authorities have said Couch’s parents are divorced.

His father, Fred Couch, has been cooperating with police during the investigation. Couch was living with his mother near Eagle Mountain Lake, an affluent area not far from Fort Worth.

According to Jordan, the prosecutor’s spokeswoman, a relative filed the missing-person report for Tonya Couch over the weekend. Anderson, the sheriff, told The Washington Post that authorities have since followed up on numerous leads but have “no concrete movement” in the case. Anderson asked anyone with information on Ethan or Tonya Couch, or the truck, to call 1-800-336-0102 for U.S. Marshals.

Since Couch’s sentencing, Anderson said, he has expected more trouble from him.

“I said then, ‘We’re not through with Ethan Couch,’ ” he said, according to the Dallas Morning News. “He’s not the kind of person who rehabilitates, who learns his lesson.”

Authorities fear that Ethan Couch may have fled the country but have vowed to track him down.

“You can run, but you’re always going to be looking over your shoulder,” Anderson said last week, according to CNN. “We’re not going to give up. We’re going to come after you. We’re going to find you, wherever you are.”

This story has been updated.

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