The swastika - symbol of the Third Reich - is banned in Germany
German authorities in the southern town of Passau have dug up a neo-Nazi's grave to remove a swastika flag that was placed on the coffin.
Police have opened a case against the neo-Nazi who witnesses say threw the flag onto the coffin during the burial of Friedhelm Busse on Saturday.
Displaying swastikas or spreading Nazi doctrines can be punished by up to three years' jail or a fine in Germany.
Police detained 11 neo-Nazis during clashes after the funeral on Saturday.
Passau police say a 45-year-old neo-Nazi is under investigation over the swastika flag incident. A police statement said he had hidden the flag inside his jacket, then thrown it onto the coffin while making a speech at the grave.
On Monday police removed soil from the grave and recovered the flag, Passau senior prosecutor Helmut Walch said, quoted by the German news agency DPA on Wednesday.
Police say about 90 neo-Nazis attended the funeral of Busse, who led the far-right Free German Labour Party, banned in 1995. He died at the age of 79.
Police say some of the neo-Nazis later assaulted two leftists at the cemetery and were detained. More arrests followed when neo-Nazis confronted police in the Bavarian town and assaulted a foreign woman.