'Affluenza' mystery: Couches' dog goes missing in Mexico - $1,000 reward

One of the enduring mysteries in the escape of “affluenza” teen Ethan Couch and his mother Tonya, who fled to Mexico recently, is what happened to the family dog.

The dog, named Virgil, is officially missing.

Described as a mix of shepherd and wolf, Virgil was on the trip with the teen and his mother when they took off to Mexico, apparently to avoid U.S. authorities after the teen is said to have violated the terms of his probation.

Virgil was last seen at a spot in Puerto Vallarta where police arrested the Couches on Dec. 28 after being tipped about where they could be found.

The Puerto Vallarta office of the organization Society for the Prevention of Cruelty to Animals, or SPCA, is circulating a lost dog poster that reads: “REWARD $1000 DOG MISSING IN PUERTO VALLARTA.”

U.S. and Mexican officials say they have no idea about the dog’s whereabouts, according to the Dallas Morning News.

“The dog was never in our possession, so I cannot deny or confirm that the dog was there,” said Rafael Mayorga, a spokesman for the Jalisco fiscal office, to the Morning News. “This is also a mystery to us.”

Meanwhile, Tonya Couch was returned to Texas on Thursday after being deported from Mexico last week.

She is expected to be arraigned Friday on a charge of hindering the apprehension of a felon when helping her son evade capture.

The younger Couch is being held at an immigration detention center in Mexico City after winning a court reprieve that could lead to a weeks or even months-long legal process in Mexico.

He received 10 years’ probation in 2013 after a manslaughter case in which his attorney pushed the theory that he could not distinguish right from wrong because of his family’s wealth and his skewed perspective.

Couch drank heavily at a party and got into a car wreck, killing four people. He was 16 at the time. Couch pleaded guilty in juvenile court to four counts of intoxication manslaughter and two counts of intoxication assault causing serious bodily injury.

The Associated Press contributed to this report.