The FBI has identified a suspected “second leaker” who is believed to have disclosed sensitive documents about the U.S. government’s terrorist watch list to The Intercept, Yahoo News reported Monday, citing law enforcement and intelligence sources. The Intercept, an investigative website, has been closely associated with Edward Snowden.

The FBI searched the house of a government contractor in Northern Virginia and federal prosecutors have started a criminal investigation into the matter, Yahoo News reported, citing sources. However, some people in the U.S. intelligence community are concerned that justice department officials may be reluctant to bring criminal charges against the disclosures because of criticism over the handling of previous leaks by the government, the report added.

There was concern "there is no longer an appetite at Justice for these cases," a source told Yahoo News on the condition of anonymity.

Marc Raimondi, a spokesman for the Justice Department, who declined to comment on the investigation, reportedly said: "Investigators are continuing to pursue it, but are not ready to charge yet."

In August, The Intercept, which is co-founded by Glenn Greenwald, who first published sensitive documents obtained from Snowden, the former National Security Agency, or NSA, contractor, had revealed that nearly half of the 680,000 people on the U.S. government’s terrorist screening databases were not linked to any known terrorist group.

The story in The Intercept was reportedly accompanied by documents “obtained from a source in the intelligence community.” However, details of the watch list system were dated as late as August 2013, months after 31-year-old Snowden had fled to Hong Kong and revealed himself as a whistleblower, Yahoo News reported.

This reportedly gave rise to speculation that there may be a “second leaker” within the U.S. intelligence community who had been providing sensitive material to Greenwald and his associates. According to Yahoo News, this was also revealed in the final scene of “Citizenfour,” a documentary on Snowden’s exposure of the NSA’s surveillance tactics.

The documentary, which released last week is directed by filmmaker Laura Poitras, a co-founder of The Intercept, and reportedly shows Snowden being excited about the new leak in the U.S. intelligence system.

The new leaker described in the film provided Snowden with a document that "outlines the rulebook for placing people on a variety of watch lists," Jeremy Scahill, a journalist at The Intercept who briefly appeared in the documentary, reportedly said during an interview last week on the radio show “Democracy Now.”

The source is "an extremely principled and brave whistleblower" who made his disclosures "at great personal risk," Scahill reportedly says in the interview.

According to Yahoo News, Scahill declined to comment about the source on Monday but claimed that The Intercept was not notified about the federal investigation.

“The Obama administration in my view is conducting a war against whistleblowers and ultimately against independent journalism,” Scahill said, according to Yahoo News.

The documents, which are being investigated, provide entries and track suspects on the Terrorist Identities Datamart Environment, or TIDE, Yahoo News reported. According to sources, the disclosures reportedly triggered the filing of a “crime report” by the National Counterterrorism Center with the justice department.

Sources also reportedly said that one of the documents in question was stamped as “Secret” and “NOFORN,” an acronym to describe the confidential nature of documents, which were reportedly less sensitive than many of those leaked by Snowden, the sources reportedly added.

"Any attempt to criminalize the public release of those stories benefits only those who exercise virtually limitless power in secret with no accountability," John Cook, editor of The Intercept, told Yahoo News.