Ethan Couch, the infamous teenager who cited “affluenza” as his defense following a drunk-driving incident in which he killed four people, is to be tried as an adult and could face up to 40 years of jail time for the 2013 crash.

Friday, a Texas judge said the case will be moved from juvenile to adult court, meaning Couch could face up to 120 days in jail, before finishing his previous sentence of ten years probation.

However if the now 18-year-old was to violate his probation again, he could go to prison for up to 40 years, ten for each person he killed.

The possible 120-day jail sentence stems from Couch’s recent probation violation in which he, and his mother, fled to Mexico.

The pair left the country in December, and sparked an international manhunt, after a video allegedly showing Couch at a party with alcohol – something that would violate his probation – surfaced online.

READ MORE: ‘Affluenza’ teen back in US custody after fleeing to Mexico

Couch’s case grasped the attention of international media when the then 16-year-old’s defence of “affluenza” (meaning his rich parents spoiled him so much he didn’t know the difference between right and wrong) proved to be a success.

Prosecutors asked for 20 years in prison, but instead Ethan was sentenced to long-term mental health treatment and ten years of probation, the terms of which stipulate that he cannot be in the presence of alcohol or drugs.

READ MORE: Runaway ‘affluenza’ teen who killed 4 in drunken car crash detained in Mexico

On June 15, 2013, Couch was illegally driving his father’s pick-up truck with friends when he crashed into a stalled vehicle on the side of a Burleson highway.

Couch killed four people, including the driver of the car and three people who had stopped to assist, two of his passengers were thrown from the vehicle and severely injured.

this is Sergio Molina, he's paralyzed, one of #EthanCouch's victims. Family still needs help @NBCDFWpic.twitter.com/4Hvc1yTZiJ — Chris Van Horne (@CVHReportsNBC5) February 19, 2016

The parents of one of the injured teens, who suffered debilitating brain injuries, sued the Couch family for $2million.

Three hours after the crash Couch has a blood alcohol level three times the legal adult limit.