A team of FBI agents that re-examined the Oklahoma City bombing after a resurgence in conspiracy theories uncovered no new reliable leads, the man who initially supervised the bureau's investigation told a newspaper.

In his new memoir, "On-Scene Commander," former FBI deputy director Weldon Kennedy criticizes those who believe federal authorities did not find all the people involved in the terrorist attack's planning. He spoke to The Oklahoman newspaper for a story in Saturday's editions.

"There's no possible way there were other conspirators," Kennedy wrote. "I can say with total confidence that we identified all three conspirators in the case and arrested them."

The bomber, Timothy McVeigh, was executed in 2001. Of his friends linked to the case, Terry Nichols is serving life in federal prison for his role in the attack and Michael Fortier spent years in prison for his crimes before being released last year.

Kennedy oversaw the agency's probe during the first couple of months after the April 19, 1995, attack on the Alfred P. Murrah Federal Building near downtown Oklahoma City. He also served as spokesman for the FBI at news conferences.

He told the newspaper that he learned of the re-examination of the bombing, which killed 168, "through my continuing association with contemporaries in the FBI and so forth."

"I've not seen any of the documents ... but I'm told that that review was very comprehensive and quite conclusive that there was ... no lead, no avenue unexplored, in the entire case," he said.

In his book, Kennedy wrote that the mysterious "John Doe No. 2" turned out to be "someone's memory playing tricks on him." FBI sketches of "John Doe No. 2" were released worldwide after witnesses said that man was with McVeigh when the bomb truck was rented in Junction City, Kan.

Kennedy said he is certain there are no others involved in the bombing because McVeigh and Nichols used a telephone calling card — purchased under a fake name — in their plot to find bombing materials and to keep in contact. The FBI was able to track where the two called.

"If there in fact was another conspirator, I am absolutely convinced that we would have been able to identify him through the telephone (records) and through other investigation that we did which was exhaustive," he said.

Kennedy, 69, was the special agent in charge in Arizona when FBI Director Louis Freeh tapped him to head up the initial bombing investigation in Oklahoma City. He retired from the agency in 1997.