April 12, 2021: -On Thursday, Former police officer Derek Chauvin’s lawyers approached wrong when cross-examining the prosecution’s expert witness, Civil Rights attorney David Henderson said.

“They did not do any damage,” Henderson told CNBC. “You don’t try to arm wrestle with a gorilla. This doctor is very clearly qualified. He knows more about medical stuff than you do.”

Dr. Martin Tobin, the prosecution’s expert medical witness, is a renowned pulmonary specialist working in critical care. He said that “Floyd died from a low level of oxygen.” Tobin’s testimony started on the ninth day of Chauvin’s murder trial.

Chauvin’s defense lawyer, Eric Nelson, suggested Tobin’s report captured only a tiny portion of what happened during George Floyd’s arrest last May. Henderson explained that instead of focusing on the medical details, the defense team of Chauvin failed to seize an “in” that Tobin gave them in testimony.

The Chicago-based physician said four key factors contributed to Floyd’s asphyxia. He told Floyd was “turned prone on the street, that he has the handcuffs combined with the street, that he has a knee on his neck, and he has a knee on his back and his side.”

Henderson added that Chauvin’s knee on Floyd’s neck was the only factor. “There are three other factors, that Derek Chauvin’s knee has to be the substantial contributing factor, that should be cross-examined on,” Henderson said. “There are three different ways that might have caused George Floyd’s death that isn’t directly attributable to, he added.”

Henderson, a former prosecutor, and CNBC contributor, also said Tobin effectively “squashed” the defense’s contention that drugs, mainly fentanyl, could have caused George Floyd’s death.