Texas teen Ethan Couch had "something akin to a going away party" before violating his probation by fleeing from the US to Mexico with his mother, Tarrant County Sheriff Dee Anderson said at a press conference Tuesday, according to ABC News.
Couch, 18, was serving 10 years of probation for killing four people while driving drunk when he was 16.
He "became known as the 'affluenza' teen during his trial in juvenile court, when a psychologist said he was so wealthy and spoiled he could not tell the difference between right and wrong," according to Reuters.
Andersaid said Tuesday that evidence proved their trip to Mexico was premeditated, citing the party. Additionally, Couch changed his appearance when he left the US, dying his hair a darker color than its natural blond.
Here's how Couch looked before and after he left the US:
Mexico officials said that they planned to release Couch and his mother Tonya later Tuesday.