West Covina police tell City News Service the man jumped into a white van outside a just-robbed credit union Monday, and police gave chase.
It led to Whittier, where the van slowed while the woman jumped on, then climbed in through a rear window.
The van soon stopped and she surrendered, but he refused.
Police sent in a dog and he scampered out as it bit his legs, cash spilling from the van.
Police say they recovered a gun tossed from the vehicle.
The man was hospitalized for the dog bite and the woman was arrested. Police have not released their names.