Three people are being sought by police in connection with two counterfeit $100 bills which were passed at separate businesses over the weekend.

A black female passed a $100 bill at Beacon Street Laundromat Friday, asking a clerk for change, Police Chief Bill Cox said.

"She received five 20 dollar bills," he said.

Two days later on Sunday, two black males in a Chevrolet Tahoe passed a $100 bill at Sonic to pay for food they had ordered.

Cox said that while the employees were making change for the bill, the manager checked its authenticity.

When he discovered it was counterfeit, he called police.

When the manager went out to check on the men he found they had left, Cox said.

"They got free food but not the change," he said.

Cox said the quality of the counterfeit bills was "reasonably decent."

"They have progressed and gotten better [at making counterfeits]," he said, noting the bills looked well used.

"It's easier to pass off used bills, people think they're legit."

While no arrests have been made, Cox said the investigator on the case, Bobby Patillo, had some good leads.

The chief noted the possibility that some of those involved did not realize the bills were counterfeit.

He urged business managers and owners to be on the lookout for counterfeits.

He said there were several ways to check for authenticity.

"The ink is added on top of the bill," Cox said. "It can be felt by running your fingernail across it, paying attention to the ridges. Also look for the watermark."

He noted that counterfeit markers used by most businesses to check bills could sometimes give a false positive.

"If you're not sure [on a bills authenticity] take it to a bank," he said. "Bigger businesses seem to check more but all [businesses] need to. This is becoming a problem."