A 78-year-old man has died hours after being mauled by his rottweiler dog as he lay on an east London street.
Police said the dog was "dangerously out of control"
Witnesses said James Rehill "looked like a doll" as the animal shook and bit him in Plaistow, on Sunday morning.
Residents tried to free Mr Rehill but it was only when police officers discharged six fire extinguishers at the dog that it released its owner.
Mr Rehill was taken to hospital suffering from severe head and facial injuries and died later that night.
Aziz Rahman, 32, saw the attack, which happened at about 0700 GMT, from his bedroom window.
He said: "There was a man lying on the floor and a dog was over him, licking and biting him.
"He looked like a doll, the dog was pulling at him.
A police officer used a fire extinguisher to scare the dog off
"There was blood all over his face."
Mr Rahman described how residents had tried to distract the dog by hitting baseball bats against a wall but the animal did not respond.
He said: "There must have been 10 to 12 police cars but nobody could do anything to get the dog off him.
"Eventually one officer used a fire extinguisher to scare the dog off."
Police have launched an investigation into the death.
A police statement said armed officers were called because the dog was "dangerously out of control".
Local taxi driver Bill Collins said he regularly saw the man walking his dog but he did not believe the animal was a "mad dog".
Newham Borough Commander Nick Bracken said: "This is a very tragic incident and our thoughts today are obviously with the family and friends of the deceased man."
He said his officers "put their lives at risk" to protect other members of the public.