Derek Landy said this quote

You think Bernadette Maguire killed him?”“Uh… no. She’s, like I said, she’s old.”“Old people can kill people too.”“I know, but…”“She could be a ninja.”“She’s not a ninja, for God’s sake. She’s somebody’s great grandmother.”“I want you to think carefully about this, Kenny. Have you ever seen her with a sword?”“What?”“How about throwing stars?”“This is ridiculous.”“Have you ever seen her dressed up as a ninja? That would have been my first clue.”The girl sucked in her cheeks so she wouldn't laugh out loud.