Oct. 19, 2009, edition of The New Yorker has a long profile of Jules Kroll. It's only available online to subscribers, but may become generally available when it's no longer the current issue. Lots of interesting detail about his business, including his selling of Kroll Inc to Marsh McLennan in 2004, but absolutely no mention is made of the crucial location of both companies' offices in WTC on 9/11. It can be viewed in the digital edition at http://archives.newyorker.com/