How oilman Charles Koch turned black gold into dark money. BBC business editor Simon Jack and journalist Zing Tsjeng investigate the feuding family that has shaped US politics for decades. The Koch family battles made “Dallas and Dynasty look like a playpen” with brother against brother, and even twin against twin. But Charles Koch succeeded as heir to the oil fortune, and spent the billions earnt from oil creating a right wing political network dubbed 'The Kochtopus'. So is he good, bad or just another billionaire?