how does liesel know that the mayors wife saw her steal the book ? where does she take liesel ??

Liesel sees three books that remain mostly intact and she steals a blue book called The Shoulder Shrug. She puts it under her shirt even though it is still hot. Although she was ignored by the workmen, Liesel realizes that one person saw her steal the book: the mayor's wife, Frau Hermann.THe Mayor's wife eventually leaves her husband's library door open for Liesel to take books.