70s or 80s movie. Around the time perios of The Car. The town police chiefs son is trying to prove that accidedntal deaths in small town are not accidents. man is killed with pruning shears, his dad dies in a car accident involving his brake lines. the killer is a man whose wife died during a surgery because of a power outage caused by a construction site.
This sounds a lot like DEAD AND BURIED (1981): http://en.wikipedia.org/wiki/Dead_%26_Buried