surrey police
Conservative politician said arrest was "unnecessary" and is "confident" investigation will end without charge.
Police say Insulate Britain protestors likely to cause "serious injury or death".
Two men and a woman in their 20s died on road close to Heathrow Airport.
The dog, reportedly called Oscar, was also killed in the collision.
Victim was taken to hospital but was later pronounced dead.
Ajae Blackwood-Petrie has not been seen since Wednesday afternoon.
Four other people taken to hospital.
Ricardo Godinho, 41, will appear in court on Monday.
The multi-millionaire died in 2012.
"West Midlands Police are being hit more than twice as hard as the likes of leafy Surrey."