BERLIN (Reuters) - German police on Monday investigated further suspicious mail packages found around the country as they tried to catch an extortionist who sent a defective parcel bomb to a pharmacy in the city of Potsdam last week. That package, which contained powerful firecrackers, wires and nails and did not explode, was found to be a criminal extortion attempt against logistics firm DHL rather than  terrorism,  German authorities said on Sunday.  DHL, owned by Deutsche Post, warned its clients on Monday that other suspect packages could arrive through its service among millions of parcels sent in the holiday season. The company said it would not change its postal secrecy principle to control the content of packages. More suspicious packages were reported to authorities around Germany - one, which German media suspected contained a grenade, was sent to the state chancellery in the eastern region of Thuringia but police found only rolled-up catalogues inside it. Police in the eastern state of Brandenburg, where Potsdam is located, said they checked 10 suspicious packages on Monday but gave the all-clear for all of those parcels. The police said a special team investigating the Potsdam pharmacy package was doubled to over 50 officials and they were searching for the extortionist. 
German police check more suspicious parcels after Potsdam explosive package