Golden Dawn member Giorgos Roupakias was facing a prosecutor on Thursday to answer charges of belonging to a criminal organization.
Roupakias, 45, has already confessed to killing 34-year-old hip hop artist Pavlos Fyssas in Keratsini, southeastern Attica, on September 17.
The murder triggered an ongoing clampdown on the ultranationalist party.
On Wednesday, magistrates investigating Golden Dawn indicated that further criminal charges will be brought against lawmakers implicated in activities linked to the party, including that of seeking to overthrow democracy.
In a report submitted to Parliament, seeking permission to lift the immunity of the three Golden Dawn MPs Giorgos Germenis, Panagiotis Iliopoulos and Stathis Boukouras, the two magistrates handling the investigation said witness testimonies had revealed that “the purpose of the organization was from the outset and remains to overthrow the democratic system.”