Investigators said the man apparently helped the group obtain documents and vehicles and was well known in far-right circles in Hanover, Spiegel Online reported Tuesday.
Media reports on the arrests of three members of a neo-Nazi group in Zwickau on charges they carried out a series of killings that for years rocked Germany. The fourth suspect allegedly joined the others in 2007 and a search of his home seemed to support that suspicion, officials said.
Research by Speigel Online indicated the four crossed paths several times, including membership in several neo-Nazi organizations.
A German federal court judge ordered the fourth suspect held in custody on suspicion of supporting a terrorist organization. The German Federal Prosecutor's Office, which is in charge of the investigation, had wanted the man detained on suspicion of membership in a terrorist group, Speigel said.