Helsinki Police are investigating a case of suspected fraud concerning four watches worth an estimated of 440,000 euros.

The owner of the Rolex watches, a luxury watch trader, said they had arranged to sell the luxury goods at a Helsinki restaurant last April. The transaction was to be completed with cryptocurrency, via a bitcoin transfer.

"The suspects of the crime misled the owner by assuring them the payment had been submitted before handing over the watches. The suspects were able to manipulate blockchain functions of the cryptocurrency," chief inspector and head of the investigation Teemu Haapala said in a statement.

Police have arrested two suspects in connection to the crime at Helsinki Airport on 8 April who have remained in custody while investigations are ongoing.

The suspects had previously purchased a Rolex watch with the same seller earlier in March. The transaction had been completed in bitcoin as agreed.

Not all suspects have been approached yet, according to Police.

Two of the stolen watches have however been retrieved and returned to the owner. The preliminary investigation also resulted in the confiscation of cryptocurrency worth approximately 136,000 euros.

"We would like to remind people that in any transaction, all parties involved should ensure that the payment is completed successfully. By the same token, buyers should also check the characteristics of the product they are purchasing. The more valuable the product in question, the more caution should be exercised regarding the agreement," Haapala said.

Police said they will be prosecuting the two detainees, following the conclusion of preliminary investigations.