Frankfurt (dpa/lhe) - After the roof truss fires in the Dornbusch district of Frankfurt on Sunday afternoon, the police assume a technical defect to be the cause. There is no evidence of third-party negligence, said a police spokesman on Monday. Further information is currently not known. The damage is estimated at 300,000 euros. Since the chimneys of the two affected semi-detached houses are in danger of collapsing, according to the police, they may not be inhabited at the moment. Nobody was injured in the fires.