FORT WORTH, Texas, Dec. 18 (UPI) -- The FBI and U.S. Marshals Service joined the effort to find Ethan Couch, the so-called "affluenza" teen whose lawyers argued he shouldn't be punished for killing four people in a drunk-driving crash in Texas because his parents were wealthy.

Tarrant County Sheriff Dee Anderson said the help from the federal agencies will expand the search globally. Couch and his mother, Tonya, disappeared after the teen missed a planned meeting with his probation officer, about the same time a video was posted on Twitter showing him attending a game of beer pong. The terms of his probation order he avoid alcohol and drugs.


Anderson said the pair could have fled the United States because they have the money to finance such a trip. But, he said, the resources from federal investigators can help.

"You can run, but you're always going to be looking over your shoulder," Anderson said. "We're not going to give up. We're going to come after you. We're going to find you, wherever you are."

Couch was 16 when he ran down four people. Defense attorneys said Couch was the victim of "affluenza" because he was spoiled by his wealthy parents and never faced any consequences for his actions, growing up with a sense of entitlement and poor judgement. He received 10 years probation in the juvenile justice system, a sentence that has been criticized as too lenient.

Investigators have spoken to Couch's father Fred, but he has not provided details about his son's whereabouts. Fred and Tonya Couch do not live together.

Prosecutors recently filed a motion to transfer his case to adult court after he turns 19 in April.