A custodian at Middletown High School in Middletown, New York, arrived to work just after 6 am on January 16th, 1986 only to find someone slumped over by one of the school's side-entrance doors; he immediately phoned local law enforcement. When police arrived, they discovered that the "someone" was only a child-- a child who had been violently and senselessly attacked. After his identity was discovered and an autopsy was performed, a full-scale investigation began. Despite strong efforts by law enforcement, nearly 37 years later we are still wondering how he got to the school, why he wasn't dressed for the weather, and (most importantly) who could have taken his life. This is the case of Shawn Edwards. 

Sources:
Various articles from the Times Herald-Record By: Oliver Mackson, Lance Oliver, Billy House, John Milgram, John Scavelli, Julie Campbell, and Tristan Corden
"Unsolved: The Horrific 1986 Killing of Shawn Edwards-- More Questions than Answers." the-line-up.com By: Orrin Gray
"Shawn Edwards Murder: How Did He Die? Who Killed Him? thecinemaholic.com By: Shraman Mitra
Crime Junkie Podcast "Murdered: Shawn Edwards Part 1" and "Murdered: Shawn Edwards Part 2"