According to the police, the first attacks took place in May, when the perpetrator placed explosive devices in three different Jumbo supermarkets – a chain of stores belonging to the Van Eerd Group – in Groningen, the largest city in the north of the country.
Subsequent attacks followed in June and July when the offender sent a congratulatory card containing a small amount of explosive substance to another supermarket in Zwolle, a small town in the province of Overijssel, also in the north of the Netherlands.
Full story: http://www.coindesk.com/dutch-supermarket-bomber-demands-bitcoin-ransoms/