"The biggest thing for me is that that there were no bodies," she said.
Leonardi, 56, remembers the burning pine and jet fuel stinging her nostrils. She said she also remembers a smoldering crater littered with debris too small to associate with the jetliner or 40 passengers and crew on board.
"I'm used to crime scenes but this one blew me out of the water. It just looked like the ground had swallowed up" the plane, Leonardi said.
"That's when I started seeing like shimmery lights . . . and it was kind of misty, and that's when I first saw, like, the angels there," Leonardi said. "And I didn't say anything to the guys because you can imagine if I would have said, 'I just saw angels on the crash site,' they'd have called the office and they'd have said, 'She lost her mind' and 'tell her to go home.' "
Instead, Leonardi kept it to herself for the better part of two years. As emotional and physical ailments surfaced that she would later learn were post-traumatic stress disorder-related, she began telling a close circle of friends and colleagues what she saw, including Kenneth McCabe, her former supervisor.
McCabe, 59, now retired near Cocoa Beach, Fla., was chief of the FBI's operational response section, which sent laboratory teams to gather evidence from each of the sites of the Sept. 11, 2001, terrorist attacks. A year or so later, he became the special agent in charge of the FBI's Pittsburgh Field Office, making him Leonardi's boss until he retired from the bureau in 2004.
"I believe her. I read the whole book," McCabe told the Associated Press. "I know she believes 100 percent that's what she saw. I know she's a sane person, so I'm not going to discount what she says she saw."
McCabe said he also understands why the Flight 93 crash site was different from the other attack scenes.
"I was there one day when they brought a busload of family members to overlook the site . . . and I teared up," McCabe said. "Just because these people had the thousand-yard stare. They didn't have any closure. They didn't have any bodies to look at. They didn't have anything to look at. At least in New York and Washington, there was the devastation [of the World Trade Center and the Pentagon] but here, except for seeing someone off in the distance, in the woods, looking for things, there was nothing."
Leonardi has befriended some Flight 93 family members, though none consented to be interviewed for this story. Asked about the book, the spokeswoman for the Families of Flight 93, Lisa Linden, issued a statement lauding the "extraordinary work" done by the FBI that also said, "The crash site and sacred ground - now central to the Flight 93 National Memorial - is a place that elicits powerful reactions from those who work at the site and who visit."
Leonardi's story has caught the attention of WQED, Pittsburgh's public television station, which featured a segment on her book in a March episode of Pittsburgh 360, a public-affairs and current-events show.
The Rev. Ron Lengwin, spokesman for the Roman Catholic Diocese of Pittsburgh, counts Leonardi a personal friend. He interviewed her on his weekly radio show, Amplify. "I have no reason to believe that she did not see angels," Lengwin said. "I think it's not surprising to me that God could choose to say that he was present there to give comfort to people, and to give comfort to the people who were there to give comfort to other people."
Leonardi still lives in Arnold, a tiny city about 20 miles northeast of Pittsburgh where she began her law enforcement career in 1984 as the town's first - and, so far, only - female police officer.
She said her primary reason for going public with her story after years of soul-searching is to heal and to bring comfort and healing to others. "The purpose of the book is to tell the story of the angels being there so that other people understand that God was there."
Leonardi, who was a teen mother and wife, said she knows what she saw, but wonders why she was allowed to see it. "You get pregnant and married at 16, that's not exactly, you know, holy material."