'Affluenza' Teen and His Mom May Be Traveling in Her Pickup Truck

As the manhunt intensifies for Couch and his mom, authorities released images of her black vehicle.

Fugitive "Affluenza" teen Ethan Couch’s mother, Tonya, has been declared a missing person, the Tarrant County District Attorney's Office said.

View: The FBI's 10 Most Wanted

Tonya is believed to be helping her son, the sheriff said on Monday, but authorities are not yet calling her a suspect in Couch's probation violation.

"Every lead is being investigated," Tarrant County Criminal District Attorney Sharen Wilson said.

Authorities say Ethan Couch's divorced father, Fred, is cooperating with investigators. He says he hasn't heard from Ethan or his ex-wife since his son failed to report to his probation officer.

Authorities released two photos of a black Ford pickup truck they say Ethan and his missing mother may be driving.

"We certainly believe they're together. We all have a strong suspicion and we believe that she's helping him and that she's assisting him," Tarrant County Sheriff Dee Anderson said in a press conference. 

Cops say if Tonya couch is indeed helping her son evade the law, she will face criminal charges. Anderson said: “We're gonna prosecute her as fully as we can if she helps him at all.”

The U.S. Marshals service has issued a wanted poster offering $5,000 reward for information leading to Ethan Couch's capture.

The website of the local sheriff's department also lists 18-year-old Couch as "Most Wanted." The FBI is helping in the manhunt too.

Read: U.S. Marshals Offer $5,000 to Help Nab Fugitive 'Affluenza Teen'

Ethan Couch disappeared after video surfaced of him at a beer pong party, a possible violation of his probation.

The D.A. says Ethan could have the book thrown at him when he's caught: “He's looking at possible penitentiary time.”

Watch Below: Affluenza Teen Can Get 10 Years in Prison for Being Spotted Partying