Grocery store bomber demanding Bitcoin ransom

The person who has been placing bombs at a number of Jumbo stores is demanding a large amount of bitcoins to stop. The police have released information about the case in the hopes that this will bring in tips that will lead to the perpetrator's arrest. The first explosive was placed in front of the Jumbo supermarket on the Wilhelminakade in Groningen somewhere during the night between May 8th and May 9th. A passerby saw a white bucket standing in front of the store and called the police. The police found an explosive substance in the bucket. Investigation revealed that such white buckets are used in the hospitality industry. The bucket also contained a white kitchen timer. On Sunday May 31st, a local resident heard a loud bang at the Jumbo supermarket on Overwinnngsplein in Groningen. A few days later camera footage revealed that this bang was caused by an explosion, which damaged the store's window and door frame. During the investigation the police found fragments of a gray timer. On June 5th Jumbo received a letter from the perpetrator. The perpetrator demanded a large amount of bitcoins, saying that he will not stop until he gets paid. The letter was posted from North- or East Netherlands and stamped in the sorting center in Zwolle. A third incident followed on June 6th. The police received a report of an explosive at the Jumbo Euroborg on Boumaboulevrd in Groningen. The store and surrounding area were evacuated and after hours of searching, no explosive was found. On July 1st the Jumbo supermarket on Veemartkt in the center of Zwolle received a birthday card containing a small amount of explosive dust. The police believe that this card was sent by the same perpetrator. Once again the card was posted from North- or East Netherlands and stamped in the sorting center in Zwolle. So far the explosives have only caused damage to property and no one has been injured. A timeline compiled by the police shows that the perpetrator sent another 12 messages in addition to the birthday card and letter demanding bitcoins. According to investigator Rob Vos, the perpetrator is believed to be a man between the ages of 20 and 40 years old. The police assumes that he lives in Groningen.