Truly Devious by Maureen Johnson
Ellingham Academy is full of riddles, twisting pathways, and winding gardens. Shortly after it is opened by Albert Ellingham in 1936, Albert's wife and daughter are kidnapped. The only clue is a riddle describing various methods of murder and signed, "Truly, Devious." Years later, true-crime buff Stevie Bell enters Ellingham Academy with a goal to solve the cold case. Then Truly Devious makes a surprising return, and another death rocks Ellingham Academy.
Review from School Library Journal:
Stevie Bell is a dyed-in-the-wool true-crime buff. And what better place to deepen her understanding than at Ellingham Academy, the Vermont private school founded in the 1930s by wealthy eccentric Albert Ellingham? Partly because the custom courses of study are tailored to students' passion—writing, engineering, film, math—but also because the school was the scene of a notorious crime not long after it opened: Albert Ellingham's wife and daughter were kidnapped, ostensibly for ransom, and a student was killed. His wife's body was found eventually, but his daughter, Alice, never was. Stevie plans to solve the case. But when a classmate is killed, everything changes. There is a lot to love here. Stevie is a smart, relatable, self-aware protagonist. The cast is racially diverse and includes teens on various parts of the gender, sexuality, and neurotypical spectrums. The setting is fully realized, and the adults are as well characterized as the students. Johnson excellently sets up both mysteries as well as Ellingham's love of puzzles, riddles, and secret passageways, but very little is resolved at the end of this series launch.