The church management of a cemetery outside Berlin has said it made a “terrible mistake” by allowing the ashes of a prominent Holocaust denier to be buried in the gravesite of a Jewish-born musicologist.

Henry Hafenmayer, a 48-year-old neo-Nazi activist, was laid to rest last Friday at Stahnsdorf South-Western cemetery in Brandenburg in a ceremony that was attended by notorious rightwing extremists including Horst Mahler, the founding member of the Baader-Meinhof group turned neo-Nazi.

Before his illness-related death in August, Hafenmayer had gained martyrdom status in German rightwing extremist circles after being sentenced to prison over a series of antisemitic letters to public institutions that described the Holocaust as a “lie”.

Photographs of the burial show that Hafenmayer’s urn was laid to rest on a burial plot in front of a gravestone of the Jewish scholar Max Friedländer, a Prussian-born singer and music scholar who died of a stroke in Berlin in 1934.

During the burial, Friedländer’s gravestone was covered up with a black cloth and a sign bearing Hafenmayer’s name and a quotation from John 8:32: “And you shall know the truth and the truth shall make you free.”

The Evangelical Church in Berlin-Brandenburg and Silesian Upper Lusatia, which manages the 200-hectare cemetery, said the burial plot had been reclaimed for new burials and Friedländer’s cremated remains removed, as is common practice with gravesites whose leases are not renewed after a “rest period” of 10 to 20 years.

Friedländer’s headstone had been left standing since it was declared a listed monument, however.

The graveyard’s management said it had rejected an initial request from the neo-Nazi’s attorney for a more centrally located funeral plot, out of fear the Stahnsdorf South-Western cemetery could become a rallying point for rightwing extremists.

A follow-up request to bury Hafenmayer at the site of Friedländer’s former grave had been granted based on the principle that every human being has “a right for a final resting place”, and because the cemetery’s register listed the musician and scholar as being a Protestant at the time of his death.

Nonetheless, the church conceded it had misjudged the situation and was looking into moving the urn containing the neo-Nazi’s ashes to another plot.

“The interment of a Holocaust denier at Max Friedländer’s gravesite is a terrible mistake and a staggering course of events in view of our history,” said Christian Stäblein, a bishop at the The Evangelical Church in Berlin-Brandenburg and Silesian Upper Lusatia. “We have to immediately look into whether we can revert this process.”

Berlin’s antisemitism officer, Samuel Salzborn, on Tuesday filed a criminal complaint at the justice department. “It is obvious that rightwing extremists deliberately chose a Jewish grave in order to disturb the eternal peace through interment of a Holocaust denier.”