Why does Tom go into two taverns in town? What does he learn while he is there?

Tom is attempting to find out where Injun Joe is hiding. He learns.....

He found that in the best tavern, No. 2 had long been occupied by a young lawyer, and was still so occupied. In the less ostentatious house, No. 2 was a mystery. The tavern-keeper’s young son said it was kept locked all the time, and he never saw anybody go into it or come out of it except at night; he did not know any particular reason for this state of things; had had some little curiosity, but it was rather feeble; had made the most of the mystery by entertaining himself with the idea that that room was “ha’nted”; had noticed that there was a light in there the night before.