The Hand on the Wall (Truly Devious, #3)
by Maureen Johnson
Not gonna say this was perfect but I sure read it fast (in bed in one sitting late into the night). Was wrong about the killer at the end of the last book, but IMO it didn't quite play fair---I'm still pretty sure it could have been the person I expected up until Stevie revealed it wasn't. Not a great fan of "the accused offed themself, justice is done" as a conclusion.
I'm also wondering about some of the other details --- how did Stevie know about the existence of the trunk at all? It's not obvious from the premises. Was it explained somewhere else why the person who opened the trunk was the only person to do so? Knocking 315 doors in a day is like... 12+ hours of work. Some typos in the ebook. But hey, it still carries you along.