A series of strange occurrences have been taking place in the city of groningen, the largest city in the north of Netherlands. A supermarket chain called Jumbo have been receiving blackmail letter asking for a large sum of money in Bitcoin. The first attack occurred in May 2015 when the blackmailer left explosives in a Groningen Supermarket. However, luckily, a member of the public stumbled upon the explosives in a bucket and it was later disarmed. Police said that the bucket is commonly used in the hospitality industry. The bucket also contained a white kitchen timer.

The key factor detectives have to work with is the fact that he is asking for Bitcoin rather than fiat or other valuable items. The features of Bitcoin are also quite helpful as it cannot be easily tracked and the money can be sold for fiat. The fact that the criminal has chosen to accept Bitcoins shows he has an interest in technology and has thought out his crimes very precisely.

Three weeks later ,on 31st May, a local resident heard a bang, it was then found out that another explosive had been planted, at another supermarket, and had exploded. The blast did not damage any civilians but did damage a window and door frame. The police also noted that fragments of a grey timer were found.

On the 5th of June, Jumbo had received another letter demanding a large quantity of Bitcoins. This letter demanded that he get his Bitcoins otherwise more attacks were to come. Police believe it was posted in the north or east of Groningen.

On June the 6th, the police received an anonymous tip claiming there was an explosive device at the Groningen Supermarket. Over fears for the public, the store was evacuated and searched for hours, however no device was found.

On the 1st of July, a birthday card containing a small amount of explosive dust was sent to a Jumbo store. The card also contained a further threat.The police stated “We have a lot of the pieces of this puzzle but a seemingly unimportant detail from a citizen could be the final piece that completes the puzzle”.