The FBI recently executed a search of the suspect's home, and federal prosecutors in Northern Virginia have opened up a criminal investigation into the matter, the sources said.
But the case has also generated concerns among some within the U.S. intelligence community that top Justice Department officials — stung by criticism that they have been overzealous in pursuing leak cases — may now be more reluctant to bring criminal charges involving unauthorized disclosures to the news media, the sources said. One source, who asked not to be identified because of the sensitivity of the matter, said there was concern "there is no longer an appetite at Justice for these cases."
Marc Raimondi, a spokesman for the Justice Department, declined to comment on the investigation into the watch-list leak, citing department rules involving pending cases.
As for the department's overall commitment to pursue leak cases, he added: "We're certainly going to follow the evidence wherever it leads us and take appropriate action."
Another source familiar with the case said: "Investigators are continuing to pursue it, but are not ready to charge yet."