More victims are surfacing in a police investigation of a fraud that has swindled residents of Suffolk out of a total of more than $35,000.

Suffolk police first issued a warning June 3 that a number of people who had recently purchased fuel at the Murphy USA station on North Main Street had been victimized. In every case, according to city spokeswoman Debbie George, the victims had used their debit card and entered a personal identification number at the pump.

Sometimes within hours, unknown suspects in California had apparently manufactured copies of the cards and used them at automated teller machines to withdraw hundreds, even thousands, of dollars from the victims’ accounts, usually after doing a balance inquiry to see how much money was available.

To date, at least 57 Suffolk residents have reported fraudulent activity with their debit cards following visits to Murphy USA, George said.

“The people that have been victims of those crimes used their debit card and inserted their PIN number,” George said. For people who had used credit cards or used debit cards as credit cards, “We’ve not seen those people be victims,” she added.

Murphy USA representatives have examined their equipment at the station and say there is no problem with their equipment.

Police initially said the victims seemed to be limited to people who had used the gas station in May, but the most recent victims used their debit cards there last week, George said.

Police have not been able to narrow down the frauds to a specific pump, George said.