Is the wife sinful for not returning two books that her husband's brother's wife entrusted to her, given her assumption that she (the latter) took them after her husband's death, and her inability to retrieve them?

The fundamental principle is that the two books are the wife's responsibility until her accountability for them is cleared, based on the Prophet's (peace be upon him) saying: "Whatever is taken by hand is guaranteed until it is returned." Therefore, the wife must endeavor to ascertain whether the two books have reached their owner. As for the accusation of witchcraft, it is not permissible to accuse others of witchcraft without clear evidence. Not everything that happens is necessarily caused by magic. Whoever fears being bewitched should resort to treatment with Ruqyah Shariah (Islamic incantation).