"Following up on the paraffin results, long-time assassination researcher Harold Weisberg and his attorney, James Lesar, obtained the raw data from Oswald's paraffin wax test through the Freedom of Information Act.53 After their analysis in Dallas, the paraffin casts had been sent to the FBI Laboratory for a more sensitive spectroscopic analysis. The FBI found the same negative result for the cast of Oswald's cheek as that obtained in Dallas. The cast was then submitted to a third analysis at the Atomic Energy Commission at Oak Ridge National Laboratories in Tennessee, where they performed neutron activation analysis using a nuclear reactor. In this extremely sensitive technique, a sample is irradiated, and the resulting radioisotopes identified through spectroscopy of the radiation, typically gamma rays, that they subsequently emit. The precise energy of this radiation is characteristic of a given isotope and therefore of the element that produced it. These scientists reported that Oswald's cheek casting "could not be specifically associated with rifle, nor could the hand samples be chemically linked to revolver cartridges."54 Concomitant with these tests, the FBI had also conducted a control study where seven different men fired the Mannlicher-Carcano rifle and subsequently had paraffin casts taken of their cheeks. Analysis of these casts using neutron activation analysis showed that, unlike Oswald, all of the men who had fired shots in the control study exhibited the presence of nitrates on their cheeks.55 Therefore, this controlled experimental analysis demonstrated that Oswald had not fired a rifle on November 22, 1963, the day of the assassination and his arrest."