 In August 2015 , members of the Dutch sport @-@ diving club <unk> <unk> dove on the wreck of the Mainz and retrieved a variety of prosaic artifacts , including a sextant and the engine telegraph . Their actions provoked criticism from German sources , who noted that the wreck was a war grave containing the remains of 89 crew members and thus should not be disturbed . The German Federal Police were investigating the incident . 
