German authorities are aware of 11 criminal offences committed since 2011 by the left-wing extremist Volcano Group, which claimed responsibility for the recent arson attack on the giant Tesla plant near Berlin. There have been other arson attacks on cable ducts, transmission masts and power supply lines, a spokesperson for the Interior Ministry said in response to an enquiry, the Sunday edition of the Welt newspaper reported. Some of the attacks had caused considerable damage, including power cuts, radio network failures and disruption to local public transport. Earlier this month, perpetrator…