WNBA star Brittney Griner reflects on 'mistake' that led to agonizing detention in Russia in '20/20' special

WNBA star Brittney Griner opened up for the first time about her harrowing monthslong detention in Russia and the “mistake” that got her sentenced to nine years in prison in a special edition of “20/20” airing tonight at 10 p.m. ET on ABC.

“I could just visualize everything I worked so hard for just crumbling and going away,” Griner told “GMA” co-anchor Robin Roberts.

Griner, 33, a two-time Olympic gold medalist and a nine-time WNBA All-Star who plays for the Phoenix Mercury, was detained on Feb. 17, 2022, at Sheremetyevo International Airport in Khimki after she was accused of having vape cartridges containing cannabis oil, which is illegal in the country.

Recounting the “mental lapse” that led her to forget the cannabis oil cartridges in her luggage, Griner said that she had awakened late on the morning she was sent to travel to Russia to play during the WNBA's off-season and she packed while she was “in panic mode.”

“My packing at that moment was just throwing all my stuff in there and zipping it up and saying, ‘OK, I'm ready,’” she told Roberts.

Griner, who reflects on the experience in “Coming Home,” a memoir set to be released on May 7, recalled the sinking feeling she had when she realized that she had forgotten two cannabis oil cartridges in her luggage after security asked her to go through her bag at the airport.

“I'm just like, ‘Oh, my God.’ Like, ‘How did I-- how did I make this mistake?’” Griner said.

“I could just visualize everything I worked so hard for just crumbling and going away.”

Griner was arrested and, after her trial was delayed for several months, she pleaded guilty to drug charges on July 7, 2022, saying that the vape cartridges containing cannabis oil were in her luggage unintentionally. She testified that she had "no intention" of breaking Russian law and packed the cartridges by accident.

“You know there are those who say, ‘Come on. How did you not know that you had cartridges in your luggage?’” Roberts asked.

“It's just so easy to have a mental lapse,” Griner said.

“Granted, my mental lapse was on a more grand scale. But it doesn't take away from how that can happen,” she added.

The U.S. State Department classified Griner as "wrongfully detained" in May 2022, which allowed additional resources to be applied to her case as the Biden administration worked to secure her release.

Griner reflected on the poor living conditions in prison as she awaited her trial, saying that she didn’t always have toilet paper and that the toothpaste they gave her had expired about 15 years ago.

“That toothpaste was expired,” she said. “We used to put it on the black mold to kill the mold on the walls.”

“The mattress had a huge blood stain on it, and they give you these thin two sheets,” she added. “So you're basically laying on bars.”

Griner was sentenced to nine years in prison on Aug. 4, 2022, and a judge denied in October 2022 an appeal filed by Griner's attorneys.

After her sentencing, Griner was transferred to a penal colony in the Russian region of Mordovia – a work camp where Griner’s job was cutting fabric for Russian military uniforms.

“What were the conditions like there?” Roberts asked.

“Really cold,” Griner said. “It’s a work camp. You go there to work … there's no rest.”

Griner said that the frigid temperatures were impacting her health and led her to chop off her long dreadlocks.

“What was that like losing that part of you, too?” Roberts asked Griner.

“Honestly, it just had to happen. We had spiders above my bed -- making nests,” she said.

“My dreads started to freeze,” she added. “They would just stay wet and cold and I was getting sick. You've gotta do what you've gotta do to survive.”

During her detention top athletes and Griner’s family, including her wife Cherelle Griner, were outspoken advocates for her release and continuously called on the Biden White House to intervene and bring her home.

Amid mounting pressure on the White House to secure her freedom, Griner was released on Dec. 8, 2022, after the U.S. agreed to swap her for convicted Russian arms dealer Viktor Bout.​​

“You said that you felt that you let down yourself, your family, your teams … how did you work through that?” Roberts asked.

“I don't think I've really gotten through all the way,” Griner said. “At the end of the day, it's my fault. And I let everybody down.”

Griner reflected on the moment she learned that she was going to be released, saying, “I was so thrilled,” but she added that she was disappointed that Paul Whelan – another American wrongfully detained in Russia – was left behind.

“I was like … are you seriously not gonna let this man come home right now?” Griner said of Whelan, who was convicted of espionage and sentenced to 16 years in a Russian prison.

Since her release, Griner has become an outspoken advocate for Americans wrongfully detained abroad.

In a heartfelt Instagram post on Dec. 16, 2022, where she thanked those who advocated for her release, Griner vowed "to do whatever I can to help” bring home other Americans wrongfully detained abroad.

“President Biden, you brought me home and I know you are committed to bringing Paul Whelan and all Americans home, too,” Griner wrote. “I will use my platform to do whatever I can to help you. I also encourage everyone that played a part in bringing me home to continue their efforts to bring all Americans home. Every family deserves to be whole.”

ABC News' Eboni Griffin, Joseph Diaz, Gail Deutsch, Susan Welsh, Netsanet Negussie, Kaitlin Amoroso, Danielle Genet and Chris Donovan contributed to this report.