Large batches of e-mail records from the Justice Department lawyers who worked on the 2002 legal opinions justifying the Bush administration's brutal interrogation techniques are missing. At a Senate Judiciary Committee hearing, Senator Patrick J. Leahy, the Vermont Democrat who leads the panel, angrily demanded to know what had happened to the e-mail files, and he noted that the destruction of government records, including official e-mail messages, was a criminal offense. He said the records gap called into question the completeness of the department's internal reviews of the work done by the lawyers in the Bush years. The Justice Department's Office of Professional Responsibility, which spent more than four years investigating the handling of the legal opinions about interrogation policies after the Sept. 11 attacks, pushed to get access to a range of e-mail records and other internal documents from the Justice Department to aid in its investigation. But it discovered that many e-mail messages to and from John C. Yoo, who wrote the bulk of the legal opinions for the Justice Department's Office of Legal Counsel, were missing. Also deleted were a month's worth of e-mail files from the summer of 2002 for Patrick Philbin, another Justice Department lawyer who worked on the interrogation opinions.