The F.B.I. agent who helped start the investigation that led to the resignation of David H. Petraeus as C.I.A. director is a “hard-charging” veteran counterterrorism investigator who used his command of French in investigating the foiled “millennium” terrorist plot in 1999, colleagues said on Wednesday.
The agent, Frederick W. Humphries II, 47, took the initial complaint from Jill Kelley, the Tampa, Fla., hostess who was socially active in military circles there, about e-mails she found disturbing that accused her of inappropriately flirtatious behavior toward Mr. Petraeus. The subsequent cyberstalking investigation uncovered an extramarital affair between Mr. Petraeus and Paula Broadwell, his biographer, who agents determined had sent the anonymous e-mails. It also ensnared Gen. John R. Allen, who now commands troops in Afghanistan, after the investigation discovered that he had sent “inappropriate communication” to Ms. Kelley.
Colleagues and news reports described the role of Mr. Humphries, in just his third year at the F.B.I., in building the case against Ahmed Ressam, who was detained as he tried to enter the United States from Canada in 1999 with a plan to set off a bomb at Los Angeles International Airport.
High-level officials at the Federal Bureau of Investigation and the Justice Department were notified in the late summer that F.B.I. agents had uncovered what appeared to be an extramarital affair involving the director of the Central Intelligence Agency, David H. Petraeus, government officials said Sunday.
But law enforcement officials did not notify anyone outside the F.B.I. or the Justice Department until last week because the investigation was incomplete and initial concerns about possible security breaches, which would demand more immediate action, did not appear to be justified, the officials said.
The new accounts of the events that led to Mr. Petraeus’s sudden resignation on Friday shed light on the competing pressures facing F.B.I. agents who recognized the high stakes of any investigation involving the C.I.A. director but who were wary of exposing a private affair with no criminal or security implications. For the first time Sunday, the woman whose report of harassing e-mails led to the exposure of the affair was identified as Jill Kelley, 37, of Tampa, Fla.
Some members of Congress have protested the delay in being notified of the F.B.I.’s investigation of Mr. Petraeus until just after the presidential election. Senator Dianne Feinstein, Democrat of California and the chairwoman of the Intelligence Committee, said Sunday that her committee would “absolutely” demand an explanation. An F.B.I. case involving the C.I.A. director “could have had an effect on national security,” she said on “Fox News Sunday.” “I think we should have been told.”