It is the fourth parcel bomb in recent months blamed on the blackmailer, who has demanded €10 million worth of bitcoins from the parcel delivery service DHL.
The latest parcel containing explosive material was sent to the Berlin Chamber of Crafts and “can in all likelihood be attributed to the DHL extortionist or extortionists,” a Potsdam police spokesman told AFP.
A female employee at the trade association contacted the police on Thursday after she noticed wires protruding from the package.
Specialists were able to defuse the parcel without having to carry out a controlled explosion.
German police have been hunting for one or more suspects ever since a DHL parcel containing nails, screws and explosive powder from Polish fireworks, was received by a pharmacy in the city of Potsdam, near Berlin, in December.
That package failed to detonate upon opening but nevertheless prompted police to clear the nearby Christmas market as a precaution.
The evacuation revived fears of the jihadist attack on a Berlin Christmas market a year earlier, which killed 12 people.
Police later discovered a message inside the package threatening further parcel bombs unless DHL made a €10-million, untraceable payment in the virtual currency bitcoin.
A similar package was sent to an online retailer in the eastern city of Frankfurt an der Oder in November, believed to have come from the same source.
Another parcel bomb linked to the extortion plot was delivered to a Berlin bank in January, containing a detonator and what appeared to be powder from fireworks. It too was defused by police.