distribution of sooting and pitting elsewhere, investigators calculated that the suitcase containing the bomb had not rested on the floor, but had probably been on top of another case, though there was no proof that the explosion had occurred in a suitcase. Using the damage to adjacent container AVN7511 to guide them, the investigators concluded that the explosion had occurred about 13 inches (330mm) from the floor of AVE4041 and about 25 inches (640mm) from the skin of the fuselage. Federal Aviation Administration (FAA) investigators then conducted a series of tests in the United States, at which Alan Feraday of Britain's Defence Evaluation and Research Agency (DERA) is understood to have been present. The tests involved using metal containers loaded with luggage, and detonating plastic explosive within Toshiba radio cassette players in garment-filled suitcases, so as to replicate the sooting and pitting pattern of AVE4041. The tests were said to have proved AAIB investigators' theory concerning both the position of the bomb and the quantity of explosive involved. The results of these tests were used as evidence at the eventual trial to determine the origin of the bomb suitcase. John Bedford, one of Pan Am's loader-drivers at Heathrow, was able to give evidence about the precise location within PA103 of the baggage container, as well as the location of suitcases inside it, all of which helped investigators piece together how the bomb suitcase came to be there. Bedford particularly remembered handling container AVE4041, he told investigators, because he was born in 1940, and his wife in 1941. Samsonite suitcase, bomb, clothes, and instruction manual An analysis by the Federal Bureau of Investigation and DERA forensic teams of the fine carbon deposits on AVE4041 and AVN7511 indicated that a chemical explosion had occurred; that a to charge of plastic explosive had been used; and that the device had exploded 8 inches (200 mm) from the left side of the container. DERA's Feraday and Dr. Thomas Hayes examined two strips of metal from AVE 4041, and found traces of pentaerythritol tetranitrate (PETN) and cyclotrimethylene trinitramine, components of Semtex-H, a high-performance plastic explosive manufactured in Pardubice, Czechoslovakia (now Czech Republic). In March 1990, Czechoslovakian President Václav Havel disclosed that the former communist regime had supplied a large consignment of Semtex through a company called Omnipol to the government of Libya. During the fingertip searches around Lockerbie, 56 fragments of a suitcase were found