The American basketball star took the stand for the first time on Wednesday, testifying that she was not given a proper explanation of what happened when she was arrested.
The American said she was only given a small portion of what was said to her by the authorities.
She said she was told to sign the papers without being told what they said.
The testimony of Griner raises questions about whether he was targeted by Russian authorities. Relations between Russia and the U.S. have deteriorated since the invasion of Ukraine. He faces up to 10 years in prison for the drug charges. Russian authorities arrested a woman after finding cannabis in her luggage. Marijuana use is illegal in Russia.
The Phoenix Mercury player wore a black shirt. She held up three photos while in a cage inside the courtroom before giving her testimony, including a picture of her law school graduation and a picture of her friends.
Lawyers say that the doctor had a note for cannabis use.