However, FBI investigators soon determined that the design data the PRC had obtained could not have come from the Los Alamos Lab, because it related to information that would only have been available to someone like a so-called "downstream" contractor, meaning one involved in the final warhead production process, and this information was only created after the weapon design left the LANL. Even though this left Wen Ho Lee apparently in the clear, the FBI continued its attempt to find evidence to implicate Lee in committing espionage for the PRC. There were 60 agents and more assigned to Lee's case, working to prove that he was a spy. The FBI conducted a search of Lee's house on April 10, seizing any item related to computers or computing, as well as anything that had notations written in Chinese. The FBI and the Department of Energy then decided to conduct a full forensic examination of Lee's office computer. The examination of Lee's computer determined that he had backed up his work files, which were restricted though not classified, onto tapes, and had also transferred these files from a system used for processing classified data onto another, also secure, system designated for unclassified data. After the FBI discovered Lee's transfer, they revoked his badge access and clearance, including his ability to access the data from the unclassified but secure network. Lee then requested from a colleague in another part of Los Alamos to be allowed to use his computer, at which time he transferred the data to a third unclassified computer network. The government then retroactively redesignated the data Lee had copied, changing it from its former designation of "PARD" (Protect As Restricted Data), which was just above the "Unclassified" designation and contained 99 percent unclassified data, to a new designation of "Secret" (which was treated on a higher security level than PARD), giving them the crime that the government needed for a formal charge. The Department of Justice constructed its case around the only real evidence of malfeasance, the downloading of the restricted information. It ultimately employed an unusual strategy of trying to prove that in addition to illegally handling information, Dr. Lee had an "intent to injure" the United States by denying it the exclusivity of the nuclear information. Lee was indicted on 59 counts, 39 of which were for mishandling information under the Atomic Energy Act of 1954, and 20 of which were for lesser violations of the Espionage Act. (The original Atomic Energy Act, a.k.a. the McMahon Act, was passed in response to the case of Cambridge physicist Alan Nunn May after he confessed to giving Manhattan Project secrets to the USSR.)