Mistakes made at the FBI's crime lab may have helped put thousands of people behind bars, based on faulty analysis of forensic evidence. The alarm bells went off in 1995, when an FBI special agent testified in the high-profile terrorism trial of the Muslim sheik suspected of plotting the first attack on the World Trade Center. A chemist and lawyer, he told the court he'd been pressured by his superiors to ignore forensic findings that didn't support the government's theory of the bombing. The uproar that followed prompted a Justice Department investigation. But the report, which took nearly a decade to complete, was never released publicly. A Washington Post report found several wrongful convictions. What about the other cases? How reliable is forensic evidence? Are new standards and oversight needed?