The convenience store cashier who was handed a counterfeit $20 bill by George Floyd — setting in motion the Black man’s ill-fated encounter with police — testified Wednesday that he watched Floyd’s arrest outside with “disbelief — and guilt.”

“If I would’ve just not tooken the bill, this could’ve been avoided,” 19-year-old Christopher Martin lamented at Officer Derek Chauvin’s murder trial, joining the burgeoning list of onlookers who expressed a sense of helplessness and lingering guilt over Floyd’s slow death last May.

Prosecutors used Martin and other witnesses to help lay out the rapidly escalating sequence of events that ended in tragedy. They also played store security video of Floyd inside Cup Foods and yet another piece of amateur footage of him outside, adding to the mountain of video documenting what happened. Together, the witness accounts and video began to show how events spun out of control, as a scene of people apparently joking around inside the neighborhood market soon gave way to the sight of officers removing Floyd from his SUV at gunpoint. Martin said he immediately believed the $20 that Floyd gave him in exchange for a pack of cigarettes was fake. But he accepted it, despite a store policy that said the amount would be taken out of his paycheck, because he didn’t believe Floyd knew it was counterfeit and “I thought I’d be doing him a favor.”

Martin said he initially planned to just put the bill on his own “tab” but then second-guessed himself and told a manager, who sent Martin outside to ask Floyd to return to the store. But Floyd and a passenger in his SUV twice refused to go back into the store to resolve the issue, and the manager had a co-worker call police, Martin testified.

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