Warren Commission Report — A new way to fight crime, called neutron activation analysis, uses penetrating neutron radiation to help catch a criminal from only a speck of evidence. The Warren Commission included the results of a neutron activation analysis test of Lee Harvey Oswald in their recent assassination study. The tests, however, could not prove that Lee Harvey Oswald fired the rifle.… Activation analysis may replace the old chemical “paraffin test” that law enforcement officials have found unreliable…. — Science News Letter, October 10, 1964
Even high-tech methods such as neutron activation analysis can’t distinguish the type of weapon fired, says Michael Martinez of the Scientific Working Group for Gunshot Residue. Tests can only determine whether a person has fired a gun, held a discharged weapon or was close to a gun when it went off. Neutron activation analysis and paraffin testing have been supplanted by a combination of scanning electron microscopy and energy-dispersive X-ray spectrometry.