He may not have cut his dreads because he did not want to start looking like the sketch in the MH case again, if he cut them, then his 'supporters" might think that he really was guilty of something.
As for dumb/ arrogant things bringing down an sk. ... The particularly bright former Col. Russell Williams, had on the very boots he was wearing when he murdered, to a police station interview. They matched the shoe print right there and then, to the print from the murder scene.
For anyone who might be unfamiliar with this case, that interview/interrogation was a masterpiece, RW ended up pinpointing where his victim's body would be located on the LE map.
That interview...
http://www.youtube.com/watch?v=zLJzNpVrcGU