Cashier Christopher Martin thought something was off with the $20 bill a customer used to pay for cigarettes last May at the south Minneapolis convenience store where he worked. The bill was just a little too blue, and Martin decided to flag a manager.

Before long, Martin saw the customer, later known to the world as George Floyd, handcuffed on the pavement and pleading for breath under the restraint of Minneapolis police, the life draining from his body.

Martin, 19, paced outside anxiously looking on in "disbelief and guilt," he testified Wednesday in former police officer Derek Chauvin's murder trial. "If I would have just not taken the bill, this could have been avoided."

Martin's gripping testimony triggered community discussions about retailers' expectations of employees to prevent theft. It also garnered sympathy for the young clerk who was thrust into an unenviable situation leading to Floyd's arrest.

Martin, who worked at Cup Foods and lived upstairs with his family at the time, testified that the store's policy was that employees who accepted counterfeit bills from customers had to cover the lost money out of their own paychecks.

Martin testified that another man came in first with a counterfeit bill and they wouldn't accept it. Then Floyd came in with a bill that the clerk was skeptical about.

Martin didn't know Floyd, but Floyd had been a friendly and talkative customer, though he appeared under the influence, Martin testified. Martin was going to let the fake $20 bill slide and pay for it himself if he had to. But after second-guessing himself, Martin decided to tell his boss.

The manager sent Martin outside to go get Floyd from the vehicle where he and others were sitting near the store. Floyd twice declined to go back inside, and Martin said he offered to cover the fake $20, but the manager instructed another co-worker to call police.

Martin later went outside as police were restraining Floyd, and Martin could be seen on video surveillance pacing with his hands over his head. He testified that he faced guilt about what happened to Floyd and later quit his job because of safety concerns.

Trial observers took to social media to voice their sympathy for Martin, criticizing store management and saying that he shouldn't have been put in that situation.

"This boy deserves a chance to start over and let go of the guilt. It was not his fault," one poster wrote on Twitter.

Another commented, "I feel so sorry for Christopher Martin. You can tell he has the weight of Floyd's death on his shoulders."

Jamar Nelson, a spokesman for Cup Foods, said employees have been told that their paychecks will be docked if they don't check bills that turn out to be counterfeit, but the store hasn't actually ever docked paychecks because of fake money. Upon hiring, employees are trained on how to determine if a bill is a counterfeit with the help of pens that turn a fake bill a different color. A money counter machine near the manager also finds fake bills, Nelson said.

It is not the store's policy to send employees out of the store to confront customers, Nelson said. But because Floyd had a good relationship with the store and managers felt Floyd might not have known the $20 bill was counterfeit, it was deemed appropriate for employees to be sent to talk to him, Nelson said.

"Floyd was a frequent patron of the store and so that's why the manager sent [Martin] back out to reason with him," Nelson said.

Peter Knapp, a professor at Mitchell Hamline School of Law, said state law is very clear that employers can't deduct wages for lost or stolen property or damage to property. A statute specifically states that wages can be deducted if the employee, after the loss has occurred or the "claimed indebtedness has arisen," voluntarily authorizes the employer in writing to make the deduction or if the employee is held liable in court.

Although threatening to take part of somebody's paycheck isn't illegal, it's not a good employer practice, he said.

Federal law does allow for a wage deduction if it doesn't take the paycheck below the minimum wage, said David Larson, a professor who specializes in employment law at Mitchell Hamline. Minnesota is one of the states that enacted its own law to protect employees from paycheck reductions from loss or theft, he said.

Larson was sympathetic to the situation Martin found himself in with Floyd. Yet there wasn't anything to prevent his manager from asking him to go out and talk to Floyd. Larson compared the Floyd scenario to asking a customer to put on a mask after that person refuses.

"You put something like this on the back of a college kid or a high school student working part time," he said. "Employers are putting their employees in an awkward situation."

Some in the local community have criticized Cup Foods for calling police. Last year, the store's owner vowed to no longer contact police for nonviolent crimes.

A review of police calls to Cup Foods over the past five years shows police have responded to the store because of a forgery a couple dozen times.

The decision on when to call law enforcement to a store for any sort of crime depends on the specific retailer and the jurisdiction where the store is located, said Mike Olson, chief executive of 360 Security Services and a former U.S. Secret Service special agent and St. Paul police officer.

Many large retailers have precise rules about when security engages with customers suspected of shoplifting or other low-level crimes, said Olson, who has worked in retail loss prevention with major retail companies.

Many retailers don't have employees directly engage with suspected criminals because of safety reasons and because they don't want employees to falsely accuse people, especially those workers who have not received proper training in security, Olson said.

Large chains like to try to review surveillance and form larger cases involving several incidents to forward to police to deter organized retail crime, Olson said. Smaller stores don't normally have the same luxury.

"Larger retail stores can weather some type of loss from fraud or theft. … Those smaller mom-and-pop stores cannot," Olson said. "That goes right against their bottom line so I think there is a sense of urgency for those smaller stores to want to immediately prevent some kind of theft or fraud from occurring."