Tanya Couch, mother of the infamous "affluenza" teen who killed four people in a drunk driving collision, was arrested Thursday after arriving back to the U.S. from Mexico.

ABC News reports the 48-year-old woman, who helped her son elude authorities by escaping the country, was taken into custody by Los Angeles Police. She was held at the Metropolitan Detention Center, awaiting Texas authorities to come take her back to her home state.

Couch is being formally charged with Hindering Apprehension of a Felon. Tarrant County's district attorney set her bail at $1 million.

Her son, 18-year-old Ethan Couch, is still in Mexico, where he fled after he failed to appear at a scheduled meeting with his probation officer. He was granted a three-day stay in his deportation case there, which may be extended at a judge's discretion, a government official said.

"We believe that, until the Mexican Federal Judge enters an appropriate order authorizing it, Ethan will not be returned to the United States," said Ethan Couch's attorneys, who are unable to practice law in Mexico, in a statement. "We are uncertain how long the legal process in Mexico will take or how it will ultimately be resolved."

Couch and his mother were apprehended in Puerto Vallarta, Mexico on Monday following a two-week manhunt by authorities in the U.S.

According to the New York Post, Ethan Couch had died his hair to avoid being recognized, and he had a gun in his possession. Employees at the Los Tules resort where Couch and his mother stayed briefly found the weapon left behind in a drawer.

Ethan Couch made headlines in 2013, when a drunk driving accident resulted in the deaths of four people, and another being permanently paralyzed. An expert witness for the defense argued that Couch suffered from "affluenza," in that he was too spoiled by his affluent lifestyle to realize the consequences of his actions.

Couch was sentenced to 10 years of probation, in which he was not allowed to drink alcohol. After an online video emerged of the teen playing drinking games, Couch left with his mother for Mexico to avoid an impending court hearing.