Originally Published: 02 AUG 22 00:15 ET

Updated: 02 AUG 22 09:14 ET

By Anna Chernova and Elizabeth Wolfe, CNN

(CNN) -- The examination of the substance contained in vape cartridges that WNBA star Brittney Griner's carried at a Moscow airport in February did not comply with Russian law, a defense expert testified Tuesday in her high-stakes drug-smuggling trial.

Among the violations is that results of the examination do not show the amount of THC in the substance, Griner's lawyer, Maria Blagovolina, said after the hearing.

"The examination does not comply with the law in terms of the completeness of the study and does not comply with the norms of the Code of Criminal Procedure," forensic chemist Dmitry Gladyshev testified for the defense during the roughly two-hour session.

The defense also interrogated prosecution expert Alexander Korablyov, who examined Griner's cartridges taken from her luggage.

Griner's appearance in the Khimki city courthouse marked her seventh hearing as Russian prosecutors accuse her of trying to smuggle less than 1 gram of cannabis oil in her luggage. She has pleaded guilty to drug charges -- a decision her lawyers hope will result in a less severe sentence -- and faces up to 10 years in prison.

Despite the guilty plea, the US State Department maintains she is wrongfully detained. Supporters of Griner, a two-time Olympic gold medalist who plays in Russia during the WNBA offseason, have called for her release over fears she is being used as a political pawn amid Russia's war on Ukraine.

US officials face immense pressure from Griner's family, lawmakers and the professional basketball community to bring her home, perhaps as part of a prisoner swap. Griner wrote to President Joe Biden pleading with him to do everything in his power to facilitate her release.

The 31-year-old sat Tuesday inside the defendant's cage in the courtroom. The charge d'affaires of the US embassy in Moscow, Elizabeth Rood, attended Tuesday's hearing and afterward said the US would "continue to support Miss Griner through every step of this process and as long as it takes to bring her home to the United States safely."

Griner's next hearing is set for Thursday.

Outside the courthouse Tuesday, one of her lawyers told CNN that Griner is focused yet nervous about the coming verdict.

"... She still knows that the end is near, and of course she heard the news so she's hoping that sometime she could be coming home, and we hope, too," Blagovolina said.

Asked about their team's strategy to challenge Russian prosecutors' evidence, Blagovolina said: "Well there are a lot of factors which should be taken by the court into account. She admitted that she did bring something, but we need to know what did she bring. What substance?"

Blagovolina also told CNN her team's experts identified "a few defects" in the machines used to measure the substance.

At trial, Griner has testified she has a doctor's prescription for medical cannabis and had no intention of bringing the drug into Russia. Following her detention in February, she was tested for drugs and was clean, her lawyers previously said.

Attorneys make the case for an 'improper' detention

Griner's attorneys have already laid out some arguments claiming the basketball player's detention was not handled correctly after she was stopped February 17 by personnel at the Sheremetyevo International Airport.

Her detention, search and arrest were "improper," Alexander Boykov, one of her lawyers, said last week, noting more details would be revealed during closing arguments.

After she was stopped in the airport, Griner was made to sign documents that she did not fully understand, she testified. At first, she said, she was using Google translate on her phone but was later moved to another room where her phone was taken and she was made to sign more documents.

No lawyer was present, she testified, and her rights were not explained to her. Those rights would include access to an attorney once she was detained and the right to know what she was suspected of. Under Russian law, she should have been informed of her rights within three hours of her arrest.

In her testimony, Griner "explained to the court that she knows and respects Russian laws and never intended to break them," Blagovolina said after last week's hearing.

The detained player testified she was aware of Russian laws and had no intention of bringing the cannabis oil into the country, noting she was in a rush and "stress packing."

Griner confirmed she has a doctor's prescription for medical cannabis, Blagovolina said, which she uses to treat knee pain and joint inflammation.

"We continue to insist that, by indiscretion, in a hurry, she packed her suitcase and did not pay attention to the fact that substances allowed for use in the United States ended up in this suitcase and arrived in the Russian Federation," Boykov, of Moscow Legal Center, has said.

Kremlin decries 'megaphone diplomacy'

The Kremlin warned Tuesday that US "megaphone diplomacy" will not help negotiations for a prisoner exchange involving Griner.

Speaking on a call with journalists, Kremlin spokesperson Dmitry Peskov said Moscow believes these talks should be "discrete."

"Megaphone diplomacy and public exchange of positions will not lead to results here," Peskov added.

The comments come less than a week after CNN reported that the Biden administration has proposed a prisoner swap with Russia, offering to release a convicted Russian arms trafficker, Viktor Bout, in exchange for Griner and another American detainee, Paul Whelan.

Russian officials countered the US offer, multiple sources familiar with the discussions have said, asking the US to also include a convicted murderer who was formerly a colonel with the Russian spy agency, Vadim Krasikov.

US officials did not accept the request as a legitimate counteroffer, the sources told CNN, in part because the proposal was sent through an informal backchannel. Krasikov's release would also be complicated because he is in German custody.

"It's a bad faith attempt to avoid a very serious offer and proposal that the United States has put forward and we urge Russia to take that offer seriously," Defense Department spokesperson John Kirby told CNN, later adding, "We very much want to see Brittney and Paul come home to their families where they belong."

Griner's family, supporters and WNBA teammates have continued to express messages of solidarity and hope as they wait for the conclusion of the trial.

Before trial proceedings last week, the WNBA players union tweeted, "Dear BG ... It's early in Moscow. Our day is ending and yours is just beginning. Not a day, not an hour goes by that you're not on our minds & in our hearts."

This story has been updated with additional developments Tuesday.

Correction: A prior version of this story misspelled Brittney Griner's first name.