In a news release issued Thursday, Upper Merion Township Police say they determined a store within The Court at King of Prussia sells replica hand grenades similar to the one found.
They believe the replica that caused the scare was stolen earlier in the day and was discarded near the Eddie Bauer Store.
When the device was initially found on Wednesday afternoon, it was unknown whether it posed a danger.
So, police evacuated about one quarter of The Court while they investigated.
The device was determined to be a fake short time later and shoppers were allowed back inside.
Police say the search continues to find the person responsible for leaving the replica grenade behind.