Close to 50 counterfeit bills passed in London

London police are warning again about counterfeit bills they say are making the rounds.

The financial crime unit is continuing to see counterfeit $100 "Scenes of Canada" series banknotes.

Since April, 46 of the banknotes have been passed in the city, police say.

They say suspects purchase a small item with the counterfeit bill so they can get genuine currency back.

The counterfeit bills seen recently in London are paper bills similar to what was in circulation from 1969 to 1979.

Police say these bills are currently out of circulation so retailers should be suspicious of anyone who presents these style of bills for payment of a retail purchase.

Police say if you witness someone attempting to pass a counterfeit bank note, call 911 immediately.