FORT WORTH, Texas — The US Marshals Service has joined the search for a teenager who was serving probation for killing four people in a 2013 drunken-driving wreck after invoking a defense that he suffered from “affluenza.”

Tarrant County Sheriff Dee Anderson said Thursday the search for 18-year-old Ethan Couch was drawing federal resources. The FBI says arrangements are being made for the bureau to join the search.

Lawyers for Couch issued a statement saying his probation officer hasn’t been able to reach him for several days, prompting authorities to issue the juvenile equivalent of an arrest warrant for the teen. They’re also seeking the boy’s mother, Tonya Couch, with whom he had been living.

Couch’s attorneys claimed at trial that his irresponsible lifestyle was due to wealthy parents who coddled him.

Video: You won’t believe what this little bastard did after killing 4 in a DUI