So Jango isn't just some random guy who answers want ads, he's a person that is sought after? Isn't that what we would expect about his character? This position is disingenuous by nature. There is nothing in the films to disprove the possibility that they looked into things but found nothing. "Not trying at all" is your own invented assumption. Such a thing is never established anywhere in the films or in any other source. In fact, ROTS establishes outright that they were looking for Sidious. That they found nothing is only a logical extrapolation of the fact that their position on the war did not change and there was no reference to significant findings.