Two families were unable to return to their homes Sunday as city and police officials monitored a possible sinkhole on the property. The families were evacuated from their duplex late Friday after several large cracks appeared on outside walls, police said. The single-story building, at 5904 Sun Glo Ave., was condemned by Port Richey city officials late Friday, police said. Officials do not know for certain whether the cracks were caused by a developing sinkhole but found the building to be structurally unsafe, police said. The owner of the property is expected to hire an engineer to conduct soil tests to determine if a sinkhole exists.