THE CASHIER WHO sold cigarettes to George Floyd and was handed a counterfeit $20 note in return has given evidence at police officer Derek Chauvin’s murder trial as prosecutors laid out the sequence of events that led to Floyd’s arrest and death.

Christopher Martin (19) said that as he stood on the kerb a short time later watching Floyd’s arrest, he felt “disbelief — and guilt”.

“If I would’ve just not taken the bill, this could’ve been avoided,” he said, joining a list of onlookers who said they felt a sense of helplessness and lingering guilt over the death last May.

Prosecutors also played store security footage showing Floyd in Cup Foods for about 10 minutes, adding to the mountain of video documenting what happened.

Martin said he immediately believed the $20 note Floyd gave him was fake, but accepted it even though store policy was that the amount would be taken out of his wages.

He said he initially planned to just put the bill on his “tab” but then second-guessed himself and told a manager, who sent him outside to ask Floyd to return to the store.

Floyd was later arrested outside, where Chauvin pinned his knee on his neck for what prosecutors said was nine minutes and 29 seconds, as a handcuffed Floyd lay face-down on the road.

The 46-year-old black man was later pronounced dead at a hospital.

Martin said that inside the store, he asked Floyd if he played baseball, and he replied that he played football, but it took him some time to respond, so “it would appear that he was high”.

The defence has argued that Chauvin did what his training told him to do and Floyd’s death was not caused by the knee on his neck, as prosecutors contend, but by a combination of illegal drug use, heart disease, high blood pressure and the adrenaline flowing through his body.

Martin went outside as people were gathering on the kerb and yelling at officers. He took out his phone and began recording, but later deleted it, explaining that the ambulance did not take the fastest route to the hospital so he thought Floyd would have died.

“I just didn’t want to have to show it [the video] to anyone,” he said.

Earlier, a Minneapolis firefighter, who wept yesterday as she recalled being prevented from using her training to help Floyd, returned briefly to the witness box.

Genevieve Hansen, one of several bystanders seen and heard shouting at Chauvin as he pinned Floyd down, yesterday described her desperation as she recounted how she was unable to go to Floyd’s aid or tell police what to do, such as administering chest compressions.

“There was a man being killed,” said Hansen.

I would have been able to provide medical attention to the best of my abilities. And this human was denied that right.

Chauvin (45) is charged with murder and manslaughter. The most serious charge against him carries up to 40 years in prison.