Q: see e.g.

http://www.fool.com/investing/dividends-income/2008/04/04/take-that-lehman-short-sellers.aspx

see also:
http://blogs.wsj.com/marketbeat/2008/03/20/hints-and-allegations-and-bear-stearns/?mod=googlenews_wsj

or search google news for Lehman CEO Fulds Securities Exchange Commission hedge funds

Are these guys smarter than us or did they actively collude? False question! Of course they are smarter than us, they also have better access to inside information than us, and they would of course conspire for profit.

The strange thing in favor of their possible legitimacy is the Bear Stearns' CEO abrupt turnaround. He lashed out at false rumors and within two (?) days says well okay the rumours are true. Did the short selling hedge funds force out the truth or create the truth? Somewhere in between is the likely answer.