1.People resented the underhanded way that he came to power.
People resented the underhanded way in that he came to power.
People resented the underhanded way in which he came to power.
People resented the underhanded way which he came to power.
Which is right? The dictionary uses the first sentence, but I feel a little odd. I tried to rephrase the last part of the sentence into normal sequence:
He came to power in the underhanded way.
So the preposition "in" is fundamental to the sentence, but why does the first sentence omit it? In which circumstances can I omit the preposition? Can I omit it when using "which"?