Robert Fisher is said to have stabbed and shot his wife and then slit the throats of his children.
He took his stuff out of the house. Then put accelerant down the hallway to the bedrooms with a candle burning on the floor. He then disconnected the gas pipe from the furnace so gas filled the house and exploded when the candle burned down. These two actions are very sophisticated and unlike for a distraught dad to do after murdering his family. The throat slit and the gunshot to the wife is also strange. If it were a spur of the moment, the throat or the gunshot would do.
Why would he slit his children's throats, if he had a gun. He would shoot them as they slept. Someone in a crazed maniacal storm would shoot and run.
Someone else killed Robert's family and told him what to do at gunpoint.
Someone told him to gather his belongings and take the dog. Someone told him to go to the ATM and withdraw the maximum amount. Robert Fisher was told to drive to the forest that he knew. The car and dog are left. Fisher is marched at gunpoint out to another vehicle. The killers take Fisher to a remote location and kill him.
Why? The mystery! No one knows but the killers who leave everyone puzzled and devastated. The story is the power. The front page. The documentary. The killers ruin his name and his family both.
And no one but the killers are in control.