The Intercessor

A grisly murder suicide, involving the deaths of twelve people, was quickly dismissed by the police as an open-and-shut case. A retired old-school detective, with too much time on his hands, decided to take it on himself to carry out further investigations. It didn’t help that the investigating detective on the case was once the retired detective’s subordinate, an arrogant know-it-all whose obstinate decisions would not be altered.
Regardless, the retired detective looked deeper into the case and the result of his investigations led him to the far reaches of the country before realising that there was far more to this case than met the eye.
He feared that the deaths had not finished, but with no resources and no real proof to back up his suspicions, how would he be able to prevent further carnage?