Former police officer Derek Chauvin’s attorneys were wrong when questioning the prosecutor’s expert, civil rights attorney David Henderson said Thursday.

“They did no harm,” Henderson told CNBC’s The News with Shepard Smith. “You’re not trying to wrestle with a gorilla. This doctor is very clearly qualified, he knows more about medical matters than you do.”

Dr. Martin Tobin, the public prosecutor’s medical expert, is a renowned lung specialist who works in intensive care medicine. He concluded that “Floyd died of low oxygen levels”. Tobin’s testimony came on the ninth day of Chauvin’s murder trial.

Chauvin’s defense attorney Eric Nelson suggested that Tobin’s report captured only a small part of what happened during the arrest of George Floyd last May.

Henderson stated that instead of focusing on the medical details, the chauvin defense team did not grab an “in” that Tobin gave them during the testimony.

The Chicago-based doctor said there were four key factors that contributed to Floyd’s asphyxiation. He said Floyd “got laid in the street, he had the handcuffs combined with the street in place, he had a knee in the back of his neck and he had a knee on his back and on his side.”

Henderson added that Chauvin’s knee to Floyd’s neck was just one of those factors.

“There are three other factors as Derek Chauvin’s knee must be the main factor. That is what you should relate to,” said Henderson. “There are three other ways that might have caused George Floyd’s death that weren’t directly related to it [Chauvin]. “

Henderson, a former prosecutor and CNBC employee, also said Tobin had effectively “suppressed” defense claims that drugs – particularly fentanyl – might have caused the death of George Floyd.

Chauvin’s defense team did not immediately respond to CNBC’s request for comment.