The Süddeutsche Zeitung newspaper reported on Tuesday that Burkhart Braunbehrens, one of the owners of Krauss-Maffei Wegmann (KMW), received a padded envelope from the "Centre for Political Beauty" (ZPS), containing a bullet and a stained note that read, "Your deals give children and their parents no chance for a happy life."
KMW is thought to be contracted to deliver 200 state-of-the-art Leopard 2-A7+ tanks to Saudi Arabia - and the German media reported last weekend that the Middle Eastern state is planning to buy up to 800 of the 60-tonne German-made tanks.
The German government has refused to comment on the reports, saying arms deals are confidential, while a KMW spokesman insisted there is no contract with the Saudis.
Last month ZPS publicly offered €25,000 for information leading to the imprisonment of the owners of KMW. "The owners belong in prison for some of the dirtiest arms deals in recent German history," said Philipp Ruch, who calls himself ZPS's "chief negotiator."
Ruch says that the collective have already received about 70 pieces of information about KMW's various owners and published them on their website.
Of the owners profiled, only Braunbehrens, an artist himself, has reacted to the activists. Speaking to state broadcaster ZDF, the 71-year-old condemned the ZPS campaign as using "mafia tactics," and said "that is stepping across the line."
But even he as a co-owner of the manufacturer admitted that exporting Leopard tanks to Saudi Arabia was "irresponsible."
The artist agreed that such a deal would be "an affront to the Arab rebellion," but argued that his influence on KMW's management was "very limited." He also claimed that he had written a letter to German President Joachim Gauck asking him to block the deal.
Left-wing daily newspaper taz reported last week that Braunbehrens had been removed from KMW's Member's Council for publicly opposing some of the company's potential deals. Neither KMW or Braunbehrens have yet confirmed this, though.