Truly Devious Series by Maureen Johnson

I have read Young Adult fiction since I no longer have a child who would be considered in the target demographic, which all in all is a shame, because I really like this genre.  My SIL, who shares that love, recommended this trilogy to me, and I very much enjoyed it.  My one recommendation is to get them all before reading the first.  The reason is that the first book especially just ends, which is annoying.  There is no attempt to wrap up a bit of the story, and move forward.  It is a straight ahead "To Be Continued" ending.  They are quick reads, so a 2-3 week period of library loan is good enough. 
The story itself takes place at a fictional high school for exceptional kids on a remote Vermont mountain top.  It flips pretty regularly between the 1930's and the present.  The past events revolve around when the founder of the school is devastated after  his wife and daughter are kidnapped.  He pays the ransom but his loved ones are not returned to him.  In the present, the school accepts a student who is obsessed with the original crime. She gets her dorm to be interested as well, and they start to investigate.  That is when the past crime engenders a current one, and the solving of the two are both linked and the heart of the story that runs between all three books.  I enjoyed this very much.