(CNN) -- Ethan Couch, known for his "affluenza" defense in his deadly drunk driving case, was released from a Texas jail Monday after serving nearly two years behind bars for violating his probation.
Couch, 20, first made headlines as a teenager when he was sentenced to probation for a drunken driving crash that killed four people and seriously injured two others.
Prosecutors in that 2013 case sought 20 years in jail, but Couch received no prison time after a psychologist testified that Couch was a victim of "affluenza," a product of wealthy, privileged parents who never set limits for him.
The decision by the juvenile court judge to put him on probation for 10 years outraged victims' families and anti-drunk driving advocates.
In 2015, Couch violated the terms of his probation and fled to Mexico with his mother, Tonya Couch. They were found and sent back to the US, where a Texas judge ordered nearly two years of jail time for Couch.
Mothers Against Drunk Driving described the two years Couch has spent in jail as "a grave injustice to the victims and their families."
"The 720 days Ethan Couch served for his crimes shows that drunk driving homicides still aren't treated as the violent crimes that they are," the organization said in a statement.
It vowed to keep monitoring the case because it "brought to light that there is so much more work to be done to hold drunk drivers accountable."
As part of Couch's current probation, he will be required to wear an ankle monitor, an alcohol detecting patch, submit to drug testing, abide by a 9 p.m. curfew and have a video interlock ignition device installed in his vehicle, according to Mike Simonds of the Tarrant County Sheriff's Office.
Couch's mother is currently facing charges of money laundering and hindering apprehension of a felon for helping her son flee to Mexico. Tonya Couch recently had her bond revoked after failing a drug test and is behind bars in the Tarrant County Jail, the sheriff's office said last week.
The deadly wreck
In June 2013, the pickup truck that Couch, then 16, was driving plowed into four pedestrians on a road in Burleson, Texas, authorities had said.
Hollie Boyles, and daughter, Shelby, had left their home to help Breanna Mitchell, whose SUV had broken down. Brian Jennings, a youth pastor, was driving past and also stopped to help. They were all killed.
Two people riding in the bed of the pickup were tossed in the crash and severely injured. One of them suffered a brain injury and filed a lawsuit against the Couch family, which was settled.
Three hours after the crash, tests showed Couch had a blood alcohol content of 0.24, three times the legal limit, according to the district attorney's office.
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