Answer:
A handsaw.
Explanation:
Rebecca Stead's coming-of-age novel "Liar and Spy" is a children's story about the main characters Georges and his friend Safer. The plot revolves around the themes of truth and lies, friendship, family, and fear among other things.
Safer had planned a whole process of spying at Georges' upstairs neighbor Mr. X. His observation was that there was something intriguing and strange about the behavior of Mr. X, who is dressed in all black and carries a suitcase always. So, keeping Georges on the lookout, he went into the upstairs apartment where he revealed he saw "a handsaw laid out on newspaper on the dining table, and it looks sharp". He further revealed that "[Mr. X] has all sorts of bleach and cleansers under his kitchen sink; three, his bathtub is very clean—“too clean".
