The thing is: there isn't a police office somewhere with a big pinboard on the wall and dozens of photos and snippets, with string joining them up to his mug shot. Which is effectively what we've go there. Often the police in various places are dealing with isolated crimes of his, that are only slowly being added together. Until he's arrested/charged with something, progress will be slow and disjointed. possibly even after that too. Most of his crimes are not immediate or violent, requiring prompt response. This is why fraud and other crimes of finance/impersonation can go unpunished for so long.
/Obvious bit