A Calgary Co-op store is dealing with this second case of food tampering.

The Oakridge Co-op, located at Southland Drive and 24 Street S.W., was closed Wednesday night.

Store officials say there was evidence some produce items had been tampered with.  Staff spent the night searching the store for any other signs of tampering. 

At the end of it, three pieces of produce were discovered with pins stuck in them.

This is the same store that dealt with a tampering issue last month. In that case, bulk bakery products, bulk food items, and packaged cheeses were recalled because they may contain small metal objects.

A criminal investigation was opened after the first incident and this latest incident has been added to the ongoing investigation.

"We have a number of suspects right now and we are going to narrow those down through a number of strategies," says Staff Sgt. Don Coleman from the Calgary Police Service.

Calgary Co-op is asking customers to check their items for any sign of tampering.

Customers who are unsure of a product they purchased may return it to the centre for a  full refund.