Activists staged vigils in dozens of German cities Sunday to commemorate the victims of a far-right terror group, one year after its existence came to light.

The revelation that a small band of neo-Nazis had likely been responsible for a seven-year murder spree sent shock waves through Germany's security establishment last year.

The group, which called itself National Socialist Underground, is suspected of killing at least nine men and a policewoman between 2000 and 2007. The male victims all belonged to ethnic minorities and for years German authorities attributed the murders to immigrant gangs.

The investigation took a dramatic turn when two fugitive neo-Nazis, Uwe Mundlos and Uwe Boenhardt, were found dead in an apparent murder-suicide on Nov. 4, 2011. The third alleged core member of the group, Beate Zschaepe, is in custody pending trial.

Zschaepe's lawyer Wolfgang Heer told The Associated Press on Sunday that prosecutors are likely to submit a formal indictment against his client "within weeks." A trial is expected next year.

Activists accuse police of failing to properly investigate a far-right link to the crimes — behavior they say is indicative of institutional racism in Germany's security establishment itself.

But the case also raised questions about the competence of Germany's federal security apparatus. According to lawmakers, officials at various agencies failed to exchange key information that could have put them on the trail of the NSU sooner.

German media have reported that prosecutors are struggling to tie Zschaepe directly to the murders and may have to charge her with lesser offenses, including arson and supporting a terrorist organization. Charges against several other neo-Nazis are complicated by the fact that some of them may have been informers for Germany's security services at the time of their alleged crimes.