WASHINGTON — A once-classified FBI memo reveals that the bureau treated a senior ABC News journalist as a potential confidential informant in the 1990s, pumping the reporter to ascertain the source of a sensational but uncorroborated tip that the network had obtained during its early coverage of the Oklahoma City bombing.
The journalist, whose name is not disclosed in the document labeled “secret,” not only cooperated but provided the identity of a confidential source, according to the FBI memo — a possible breach of journalistic ethics if he or she did not have the source’s permission.
The ABC employee was even assigned a number in the FBI’s informant database, indicating he or she was still being vetted for suitability as a snitch after providing “highly accurate and reliable information in the past” and then revealing information the network had obtained in the hours just after the 1995 terrorist attack by Timothy McVeigh.
To read more click here. 
UPDATE (Tues; 5:15 p.m.): John Cook of the website Gawker reports  that the ABC journalist was Christopher Isham, now a vice president at CBS News and the network’s Washington bureau chief.
Cook writes: “Isham’s tip was of course not true, and ABC News never reported it. But the FBI found him useful enough to open an informant file on him, and circled back a year later to ask who his or her source was. Astonishingly, Isham gave him up:
“Nearly a year later, the network staffer was contacted by the FBI and agreed to divulge ABC’s source for the uncorroborated claim: a former CIA officer named Vincent Cannistraro, who was on contract to the network as a consultant, who, in turn, had gotten the information from a Saudi general.”
To read Cook’s full story click here.