Someone killed at least four children in Oakland County, Mich. between 1976 and 1977.
Investigators have been working for decades to determine who the serial killer is and if he is still alive. Those who knew the victims -- their families, friends, classmates, teachers, coaches and neighbors -- have been forever changed by what happened during the 13-month period from February 1976 to March 1977.
In that time, the four children were abducted and murdered with their bodies left in various locations within or just outside Oakland County.
The largest task force in U.S. history at the time was assembled to try and find the child killer. Decades later, without a conviction, questions about the investigation have surfaced, including questions of mishandling evidence and clearing suspects prematurely.
Timothy King's father has sought the files related to the death of his son, but Oakland County Prosecutor Jessica Cooper has denied his requests.
King started his own investigation and in 2010, he said he was sure a man named Christopher Busch killed his son, despite Busch passing a polygraph test.
Other leads have connected the case to several suspects. Could one of them be the Oakland County Child Killer? Could investigators have done more?
Watch Child Killer Chapter Five: Suspicion in the video player above.