The Bank Robbers are minor antagonists in the first Captain Underpants novel, and the movie.
They do not speak in the film nor the first book.
The bank robbers first appear in the first Captain Underpants novel, The Adventures of Captain Underpants when George and Harold find Captain Underpants at a bank as Captain Underpants confronts two bank robbers when they robbed a bank and Captain Underpants orders them to surrender and said to them "Or I will have to resort to Wedgie Power!".
The bank robber duo fall down in hysterics and got arrested by the police. After Captain Underpants defeats and confronts the two bank robbers, they were never seen again in the rest of the chapters or pages of the novel. In fact, they never appeared in the rest of novels.
The bank robbers appear in the film when they get out of the bank after they robbed the bank by stealing money but they were immediately defeated by Captain Underpants landing on top of them which causes money to go everywhere. it is unknown what happened to the bank robber duo since they were never seen again for the rest of the film. So, it is possible if they were arrested by the police.