Philippine investigators on Sunday combed through the smouldering wreckage of a Manila slum, hunting for more victims of a cargo plane crash as well as clues over the accident that left at least 13 dead. The small aircraft plunged into the shanty town on Saturday, exploding on impact and causing a fire that gutted a 2,000-square-metre (half-acre) section of the slum that stands either side of an open sewer. The crash killed both the pilot, co-pilot, and a third person on board while the other fatalities were residents who died in the resulting inferno. Five others were reported missing, according to residents, while at least 20 more people were injured. Emergency crews said they were carefully sifting through the rubble in hopes of finding bodies beneath, although an early morning search turned out negative. \"No more bodies were found this morning,\" Philippine National Red Cross secretary general Gwendolyn Pang told AFP. \"DNA testing will be done today on those who had been recovered to identify them. They were burnt beyond recognition.\" Pang said that the injured sustained serious burns and were being treated at a hospital, including seven children who had been playing near the site where the plane crashed. Experts from the civil aviation authority said they were trying to recover the burnt-out engine of the crashed plane, as well as other debris that could yield clues as to what caused it to plummet into the slum. \"We want to get the engine block, and we will also check the records of the aircraft and the pilot, including that last conversation with the control tower,\" said Amado Soliman, of the agency\'s accident investigation board. The four-seater planed had just taken off Manila\'s domestic airport Saturday when it radioed the control tower for permission to return and land, but instead crashed into the shanty town. It was to have picked up cargo from the nearby island of Mindoro and was believed to have been carrying a full tank of fuel when it went down. The blaze also engulfed a nearby elementary school, but it was empty at the time of the weekend crash -- avoiding what would have been much bigger casualties. Florencio Bernabe, the mayor of Paranaque district where the crash occurred, said that at least 50 shanty dwellings burned down and called for compensation for the families of the victims. \"We\'ve already found out the owner of the aircraft, and they need to be accountable,\" Bernabe told reporters. Ramon Gutierrez, head of the local Civil Aviation Authority, said that a full investigation into the cause of the crash was ongoing. The accident has trained the spotlight on the country\'s problems in dealing with unfettered urban development and the lack of enforcement of zoning laws. More than 2.5 million people - or about a quarter of Manila\'s population -- now live in slums, many of which have sprung up near open canals, sewers and just across the fence from the capital\'s main airport. Deadly fires are common with many of the shanty towns constructed of light materials that easily catch fire. Up to 30,000 people lost their homes in successive slum fires in Manila in February, while in January, 12 people, most of them children, were killed when a fire razed an impoverished coastal area.