Derek Chauvin: Police officer on trial for murdering George Floyd invoked his Fifth Amendment right

The defence side drew to a close when Chauvin informed the court that he would not testify, saying he would invoke his Fifth Amendment right not to take the stand.

"Is this your decision not to testify?" Judge Peter Cahill asked.

"It is, your honour," Chauvin said.

Photo by HANDOUT/Hennepin County Jail/AFP via Getty Images

The prosecution briefly recalled a lung and critical care expert to knock down a defence witness's theory that carbon monoxide poisoning from a squad car's exhaust might have contributed to Mr Floyd's death.

Dr Martin Tobin noted hospital tests that showed Mr Floyd's level was at most 2%, within the normal range.

With that, both sides finished presenting their cases.

Photo by STR / Court TV / AFP

Closing arguments are set for Monday, after which the jury will begin deliberating.

The decision not to testify was announced a day after a forensic pathologist testifying for the defence said that Mr Floyd died of a sudden heart rhythm disturbance as a result of his heart disease.

That contradicted prosecution experts who said Mr Floyd succumbed to a lack of oxygen from the way he was pinned down.

The defence witness, Dr David Fowler, said on Wednesday that the fentanyl and methamphetamine in Mr Floyd's system, and possibly carbon monoxide poisoning, were contributing factors in the 46-year-old black man's death last May.

Chauvin lawyer Eric Nelson has argued that the 19-year Minneapolis police veteran did what he was trained to do and that Mr Floyd died because of his illegal drug use and underlying health problems.

Prosecutors say Mr Floyd died because the white officer's knee was pressed against Mr Floyd's neck or neck area for nine-and-a-half minutes as he lay on the pavement on his stomach, his hands cuffed behind him.

But Dr Fowler said that Chauvin's knee on Mr Floyd was "nowhere close to his airway" and that Mr Floyd's speaking and groaning showed that his airway was still open.

Chauvin, 45, is charged with murder and manslaughter over Mr Floyd's death after his arrest on suspicion of passing a counterfeit 20-dollar note at a neighbourhood market.

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