BERLIN -- Three elderly men alleged to have served as SS guards at the Auschwitz death camp have been released from custody, but prosecutors say the investigation against them continues.

Stuttgart prosecutors' spokeswoman Claudia Krauth said a 92-year-old suspect was released Thursday but had to pay a bond and give up his passport. A 94-year-old and an 88-year-old were released over the past week.

Krauth says her office didn't object because it was not necessary for the investigation to have the three in custody. They were all incarcerated in February after prosecutors said there was significance evidence that they could be charged as accessories to murder for serving as Auschwitz guards.

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Krauth says "that suspicion hasn't changed."

They're among about 30 Auschwitz guards under investigation nationwide.