AfD party leader Frauke Petry
AfD party leader Frauke PetryReuters

The German Prosecutor has opened an investigation against Rudolf Muller, a member of the extreme right-wing Alternative for Germany (AfD) party, on suspicion that he sold medals with swastikas and banknotes from extermination camps in his antique shop in the Western German city of Saarbrucken.

Muller is one of the senior politicians in the party, which has advocated stiff opposition to Muslim immigration to Germany. In the past members of the party were involved in a significant number of anti-Semitic incidents.

Muller admitted in his investigation that he had sold the Nazi artifacts but claimed that he was unaware that this contravened the German law forbidding the sale of "symbols of unconstitutional organizations." The law does not detail which artifacts cannot be sold.

In an interview with the German media, Muller said that he does not believe that his actions were illegal. "This is certainly not an immoral or criminal act," he said.

The uproar over the sale of Nazi artifacts comes days after Kay Nerstheimer, a recently elected member of the AfD party, aroused angry responses and a summons to a police investigation for calling Syrian migrants "disgusting worms" in a number of posts on his Facebook site.

The Alternative for Germany party recently scored successes in local elections in a number of German states. In the Berlin elections, the party received 14.2% of the vote while also registering high rates of success in other states. The party's leaders have attacked Chancellor Angela Merkel in recent months over her liberal immigration policy. The head of the party, Frauke Petry, has dismissed in the past few days media allegations of ant-Semitism in her party and claimed that these were "scandalous assertions."