Toronto police are warning taxi cab users to be vigilant with their bank cards after dozens of people reported losing $40,000 from their accounts.

According to police, some taxi cab passengers have been asked to enter their personal banking information into a PIN-pad device when they ask to pay by debit.

The device registers their personal password but doesn't process the transaction.

"The customer for whatever reason is distracted, either on their cell phone, or maybe they've had a bit too much to drink and they don't realize that the transaction is never processed," Det. Const. Michael Kiproff told CTV.ca.

"Not only that, the driver gives them back a bank card that's not theirs," he said.

Kiproff believes these bank cards are then being used to withdraw money at bank machines.

About 50 people have been swindled out of a few thousand dollars each, Kiproff said. About $40,000 has been stolen so far.

"People don't realize they've got the wrong card until the next time they try and use it," Kiproff said.

The detective said he's been investigating the case for the past six months. While there have been reported incidents in the downtown entertainment district, there have also been complaints in midtown Toronto around the upscale Yonge Street and Eglinton Avenue area.

Police have several pictures of a suspect, taken from bank security cameras and even a passenger's cell phone. They've distributed his picture to cab companies but so far, they don't have any leads on the suspect's identity.

Kiproff said he's not sure yet whether the suspect is a legitimate taxi driver.

Anyone with information is asked to call the fraud unit at 53 Division, 416-808-5307. An anonymous tip can be left with Crime Stoppers at 416-222-TIPS.