Drygalla left the Olympic village earlier than planned last week after her companion's extremist links became known.
Her women's eight team had already failed to make the final in London by the time she left.
German news agency dapd reported Thursday that Rostock prosecutors suspect Michael Fischer and a dozen others of attacking a memorial event for the victims of a murderous neo-Nazi group.
One police officer was injured during the standoff in February.
Dapd said Fischer could face a prison sentence if convicted of serious breach of the peace.