Brittney Griner walked with her head down as she left her court trial in suburban Moscow Thursday.The All-Star center for the WNBA's Phoenix Mercury and two-time Olympic gold medalist pleaded guilty to drug possession and smuggling charges.Russian authorities said they discovered cannabis vape cartridges in her luggage, but she told the judge she had no intention of committing a crime."She is a responsible person, and she admitted that it was hers," Griner's lawyer, Alexander Boikov, said. "But, she said that it was unintentionally brought to Russia because she was in a hurry as she was packing."The confession came just days after Griner wrote a handwritten letter to President Joe Biden, pleading for him to bring her home.President Biden spoke with Griner's wife, Cherelle, after reading Brittney's letter and assured her he was working on Brittney's release as soon as possible."Most important, I was able to share with Mrs. Griner a letter from President Biden. And Mrs. Griner was able to read that letter," U.S. Embassy's Deputy Chief of Mission Elizabeth Rood said.But, the call with the president and the letter sent to the basketball star did little to ease her wife's worries."I can't rest as her safety is in question," Cherelle Griner said.She expressed her frustration overnight at a rally in Phoenix, calling for her wife's swift and safe return home. "I'm frustrated those 140 days have passed since my wife has been able to speak to me, to our family and to her friends," Cherelle said. "I'm frustrated that my wife is not going to get justice." Brittney Griner was detained in a Moscow airport nearly five months ago after the cartridges were allegedly discovered. The charges against her carry a 10-year prison sentence."I would like to, again, emphasize the commitment of the United States government at the very highest level to bring home safely Mrs. Griner and all U.S. citizens wrongfully detained," Rood said.A Russian deputy foreign minister warned that Americans speaking out "don't help the practical settlement of issues," but Griner's supporters and friends at the rally in Phoenix made their stance clear."We are not going to ever be quiet until she's home safely," Cherelle said.Griner is expected to be back in court next Thursday.