On August 18, 2012, about 2006 Atlantic daylight time, a Bell 206B, N118EC, was substantially damaged following a loss of engine power and hard landing at San Juan, Puerto Rico. The commercial-rated pilot, commercial-rated co-pilot, and one observer were not injured. The helicopter was registered to a private corporation and was operated by the San Juan Police Department as a public use flight. Visual meteorological conditions prevailed and a visual flight rules flight plan was filed. The flight originated at Isla Grande Airport (TJIG), San Juan, Puerto Rico, about 1930. The pilot reported that the helicopter was serviced with 25 gallons of Jet A fuel about three hours prior to the flight. Combined with 35 gallons already in the tank, the total fuel on board was 60 gallons. The flight departed TJIG at 1930 on a routine surveillance mission in the Rio Piedras and San Juan Metro area. About 2000, the crew smelled a fuel-like odor and decided to return to TJIG. About five minutes later, the fuel pump warning light illuminated and the engine lost power. The pilot elected to perform an autorotation in a nearby parking lot. The helicopter landed hard and the main rotor blades contacted and partially severed the tail boom, forward of the tail rotor assembly. Neither pilot, in their written statements, mentioned any observation of the fuel tank gauge in flight. Federal Aviation Administration inspectors responded to the accident site and documented the condition of the wreckage. The inspector confirmed substantial damage to the helicopter. The wreckage was then recovered to the operator's facilities where a subsequent examination was performed. The examination revealed no evidence of fuel in the fuel tank. The fuel tank was undamaged. The fuel gauge read "zero" gallons when power was applied to the electrical system. There were no leaks found in the fuel lines and the fuel cap was secure. Testing of all fuel system components revealed no evidence of a malfunction or failure. Fuel was added to the fuel tank and no leaks were observed. On August 22, 2012, the engine from the accident helicopter was removed and inspected. External and internal examination, utilizing a borescope, revealed no mechanical anomalies or damage. The engine was then installed on another company helicopter to accomplish a test run. The helicopter was serviced with 60 gallons of Jet A fuel to simulate the accident flight conditions. The engine was started and ground run for 25 minutes, followed by 15 minutes in a hover. The fuel consumed in the 40-minute period was 12 gallons. Historical records for the accident helicopter revealed that the average fuel burn was about 20 gallons per hour. All engine parameters during the test run were in the normal range and no fuel leaks were noted.