Police have been ordered to detain Ethan Couch, a North Texas teen whose lawyers attributed his deadly drunken driving crash to "affluenza," because his parole officer has been unable to reach him or his mother, his attorneys said.

On Thursday afternoon, Tarrant County Sheriff Dee Anderson said the U.S. Marshals have officially joined the search to find Couch.

In a controversial decision that garnered national attention, Couch was sentenced to 10 years of probation after admitting responsibility in the DUI crash that killed four people in June 2013. A judge also ordered him to a rehabilitation facility.

The defense's strategy included testimony that Couch suffered from "affluenza," a diagnosis not recognized by the American Psychiatric Association which refers to an upbringing so privileged that a person is unable to discern right from wrong.

Earlier this month, a six-second video posted on Twitter showed young men playing beer pong. The person who posted the tweet accused Couch of violating his probation, which prohibits Couch from driving and using drugs or alcohol.

Couch's attorneys, Regan Wynn and Scott Brown, released the following statement Tuesday afternoon:

"We have recently learned for last several days the juvenile probation officer has been unable to make contact with Ethan or his mother, with whom he’s been residing. It’s our understanding that the court has issued a directive to apprehend to have Ethan detained (sic) because he is out of contact with his probation officer. We do not have any further information concerning this situation. It would not be appropriate for us to publicly discuss this matter further at this time."

After the tweet, Couch's attorneys said they were conducting their own investigation into the allegation. Officials have not confirmed the contents of the video or issued any charges related to the claim.

Police have been ordered to detain Ethan Couch, a North Texas teen whose lawyers attributed his deadly drunken driving crash to “affluenza,” because his parole officer has been unable to reach him or his mother, his attorneys said.

Fugitive Unit Looking For Couch

Tarrant County Sheriff Dee Anderson confirmed that a “directive to apprehend”, the juvenile equivalent of an adult warrant, for Ethan Couch hit the system Wednesday morning.

That directive is in a national database for law enforcement officers. Anderson says the department’s fugitive unit is actively searching for the teenager.

“He’s gone, he’s run and we don’t know where he is,” Sheriff Anderson said.

Anderson confirmed what Couch’s attorneys stated, saying that Couch missed an appointment with his probation officer. While that’s not uncommon, when juvenile services went to speak with Couch and his mother Tanya, they couldn’t be found.

“They went out to his mom’s house, where he’d been staying, and clearly there was no one there,” Anderson said.

The Tarrant County District Attorney’s office confirmed it was still investigating the Twitter video, but said they too were looking for Couch.

Anderson fears he might be long gone, however.

“If he’s here, if he’s somewhere in this part of the world, we’ll find him,” Anderson said. “But I’ve got a bad feeling that he’s gone and I don’t think he’s gone a short distance.”

Tarrant County Sheriff Dee Anderson says his deputies are looking for Ethan Couch, the teenager who killed four people in a 2013 drunken-driving wreck — and claimed as part of his defense that he suffered from “affluenza.” Anderson said he believes Couch is on the run and has fled with his mother.

Anderson said he wasn’t surprised to see Couch in trouble with the legal system again, roughly two years after admitting responsibility in juvenile court for the fatal crash and his subsequent sentencing trial where the “affluenza” defense was used.

“He never, after killing four innocent people, showed one instance of any regret or remorse and, so, I felt like he would never successfully complete his probation,” Sheriff Anderson said.

Juvenile Services was unable to comment on Couch’s case, as it’s in the juvenile court system.

However, they were able to describe the process of what will happen if and when Couch is taken into custody. Any juvenile apprehended through one of these orders will be taken to the Lynn W. Ross Juvenile Detention Center in Fort Worth.

The individual will remain at the juvenile detention facility until an appearance before the judge. That hearing will typically happen the next work day. It would then be up to the judge to impose any kind of punishment, based on the violation of the probation.

Aside from the state hospital stay and 10 years’ probation, details on what constitutes a probation violation were never publicly released.

Lawyers representing Ethan Couch confirm police have been ordered to detain their client since his parole officer has been unable to reach either he or his mother.

The judge in the 323rd District Court is no longer Jean Boyd, as she did not run for re-election. Judge Timothy A. Menikos now oversees the juvenile court.

The district attorney’s office is waiting for a hearing in juvenile court as officials attempt to move Couch’s probation from juvenile oversight to adult court. The DA’s office wants that to go into effect on Couch’s 19th birthday in April. There’s no word on when that hearing will be and since it is in juvenile court it is typically not announced.

While Couch is now 18 years of age, because his crimes occurred when he was a minor he remains under the jurisdiction of the juvenile justice system.

Neighbors at Eagle Mountain Lake React

Couch lived with his mother in a rental house on Eagle Mountain Lake but moved out this summer, the owner said.

With the exception of this pinball machine in a back room, the house now appears empty.

The owner, James Walker, of Kent, Washington, said Couch and his mother left at the end of August when Walker wouldn't renew their lease.

He declined to explain why, and it's not clear where the two had been living before they disappeared, sometime in the last few weeks.

A neighbor at Eagle Mountain Lake said Ethan Couch seemed nice enough.

"He's polite and respectful," said Roger Lingenfelter, who lives next door. "I only talked to him a couple times, you know. He treated me with respect and that was about it. Just seemed like an average kid to me."

Lingenfelter said he noticed parties at the Couches' house.

"Well, it's a lake, you know, so it happens," he said.

He remembered an especially large party for the Fourth of July.

"They had a huge fireworks display," Lingenfelter said. "It was enormous."

Ethan Couch's father, Fred, told investigators on Thursday that he hadn't seen his son or his ex-wife in two weeks and had no idea where they were, according to a person familiar with the case.

NBC 5's Scott Gordon and Chris Van Horne contributed to this report.