The project started in March 1952 as a follow up to the Sign and Grudge Projects, to find explanations to all the UFO sightings, to know if there was any reason to fear them as a threat to national security, and to know if the UFOs used any kind of advanced technology that could be useful to the US. Thousands of reports were collected, analysed and filed according to their results and there seemed to be no problem until one of the persons who worked in the investigation team sent in his own sighting. It was filed but later when he wanted to go back and refer to it the report couldn't be found. It had disappeared. He understood that reports that were unexplained and could cause fear in the public were sorted out of the files of Blue Book and passed on to a higher authority. A result of the Condon Report Project Blue Book was shut down in 1969. This project was the last publicly known UFO research project led by the USAF. One of the investigators at Blue Book, Dr J. Allen Hynek, went on to start the first scientific based UFO group, the centre for UFO Studies, in 1973