Secret memo suggests FBI had a mole inside ABC News in 1990s

Update at 5:56 p.m. ET: Gawker claims it knows who the mole was: Christopher Isham, now the Washington bureau chief for CBS News and a network vice president. He declined to comment, and a CBS spokeswoman said, "This is a matter for ABC News."

Read Gawker's report to see how it deduced the informant's ID -- and how CBS responded to the initial report.

By Douglas Stanglin
USA TODAY

Original post: A once-secret memo shows that the FBI treated a senior ABC News journalist as a potential confidential informant in the 1990s, beginning with information the reporter supplied at the time of the Oklahoma City bombing, The Center for Public Integrity reports.

The journalist's name is not disclosed in the document, which is labeled "secret."

But it shows that the journalist not only cooperated with the FBI in the 1995-96 period, but provided the bureau with the identity of a confidential source in what the center calls a possible breach of journalist ethics.

The center quotes one journalism professor as saying that the fact that the journalist was given an informant number and had contributed information in the past indicates he or she was sharing the information in the public good.

ABC News tells CPI that it is not certain about the identity of the journalist, but does not believe he or she still works for the network.

Spokesman Jeffrey Schneider tells the center, however, that the FBI description of its interactions with the reporter raises serious concerns about intrusions on the First Amendment.

The memo was recently discovered by a Utah lawyer who found it -- unredacted and still marked 'secret' -- in a box of documents gathered by attorneys for Terry Nichols, a defendant in the Oklahoma City bombings.