question about Bulstrode

You don't get Bulstrode's background from the miniseries.

In the book we learn that he was a former associate of Raffles'. He was a petty con man who got respectability by marrying his wife, who was wealthy. In his past he cheated Will Ladislaw out of his fortune by hiding his mother's identity.

Then he found God (but George Eliot makes it clear that his conversion is genuine) and became holier-than-thou, thus making enemies all over Middlemarch.

The genius of Eliot is that even when he gets what he richly deserves, we still pity him.

He married his employer's widow, thus gaining full ownership of the pawnshop and its (apparently) lucrative trade. Pawn shops often dealt, knowingly, in stolen goods, so were not regarded as respectable. As previously posted, Mr. Bulstrode found out where his wife's runaway daughter was, and concealed his knowledge, thereby retaining all of the family money for himself, and leaving the daughter (mother of Will Ladislaw) in poverty. Later, in Middlemarch, Mr. Bulstrode further increased his wealth by the banking trade. He was a hardnosed creditor to many in the town, with his unpopularity further compounded by his facade of piety.

Before I look at the answers to your question let me tell you that I was just about to post the same question. I wondered if I had missed something.