The Justice Department is going through thousands of cases from the days before DNA testing to see whether the government exaggerated the significance of the FBI's hair analysis. The review, the largest in U.S. history, will focus on work by FBI Laboratory hair and fiber examiners since at least 1985, the Washington Post reported. A reporter at the Post had been working on a story about Donald Gates, a D.C. man released after DNA evidence proved his innocence, when he learned about Frederic Whitehurst, an FBI lab chemist who blew the whistle on the FBI Laboratory in the mid-1990s. Whitehurst said he watched colleagues contaminate evidence and, in court, overstate the significance of their matches. When Whitehurst, a chemist with a doctoral degree from Duke, arrived at the FBI crime lab in 1986, the first thing he noticed was that the place was, as he called it, a pigsty. The equipment was outdated and there was a film of black soot coating the counters - a dust from the vents that the agents called black rain." After the first World Trade Center bombing, Whitehurst testified that supervisors pressured him to concoct misleading scientific reports. When he refused to testify that a urea nitrate bomb had been the source of the explosion, the FBI found another lab technician to testify. He learned that an agent had, for the previous nine years, rewritten his scientific reports to support the prosecution.