PITTSBURGH (July 3, 2012)—Lillie Leonardi, a former FBI employee with post-traumatic stress disorder linked to her role in the investigation of the 9/11 terrorist attacks, has written a book in which she describes seeing legions of angels guarding the Pennsylvania site where a hijacked airliner crashed.

Leonardi, who was a Pittsburgh-area police officer before working for the FBI, says she wrote her book, "In the Shadow of a Badge: A Spiritual Memoir" to encourage people dealing with PTSD and those who continue to look for comfort and answers about the terrorist attacks that day.

Leonardi, 56, a divorced grandmother, says she's convinced she saw the angels.

But what she's questioning in her book is why she was allowed to see them.