The "secrecy" behind this investigation is starting to look very suspicious. Apparently, last night they had several witnesses who gave a description of the man (/men).
So where is the composite photo of the "man-we'd-like-to-talk-to-who-might-have-some-valuable-information-but-who-isn't-a-suspect"? They had several hours to prepare it...
That is standard operating procedure when any big disasters/crimes happen. Government suffers from the '1938 War of The Worlds' syndrome.