I think it is a fallacy to believe only highly intelligent people can plan or get away with murder, or that only dumb people get caught. I’d say Douglas Garland was highly intelligent yet he was caught. Robert Pickton - not a high IQ but got away with many murders for a long time before he was caught.
Was Bruce MacArthur smart because he got away with it for years, or dumb because he was eventually caught?
I think, if we look at many murders, we would see a mix of both smart and dumb folks caught for their crime.
In this case, how smart would someone need to be, hypothetically, to strangle a child and dispose of their body in a large barely inhabited forest area where they’ve lived all their life, while owning an all terrain vehicle? How much incriminating evidence might by left behind?
IMO