Read the following exert from the novel:
"But...but that can't be," Lizzie sputters. "We sent money to-"
FJ shoots Lizzie a fast look, and the rest of her words fade away. "Here you go, Frankie Joe," he says. "Set your bike up there on the porch with the others."
What can you infer about the reason FJ "shoots Lizzy a fast look" ?