By BEN CLERKIN

Last updated at 11:34 01 February 2008

A grandfather was mauled to death by his Rottweiler after he collapsed in the street.

The man, believed to be James Rehill, 78, fell to the ground while he was taking the dog for a walk.

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At first, the animal tried to revive its master by licking and pawing him, witnesses said.

But it became more and more agitated and started biting and mauling him.

Passers-by tried to scare the dog off by sounding car horns and banging sticks.

But it took no notice and continued to maul the retired labourer's face and hands.

The ten-minute attack, in Newham, East London, on Sunday, ended when a policeman fired a fire extinguisher at the dog.

It was later destroyed by police marksmen.

The father-of-two was taken to the Royal London Hospital in Whitechapel but died on Sunday evening.

It is thought the dog was wearing a muzzle but that it somehow came off or broke.

Aziz Rahman, 32, saw the attack, which took place outside his house. He said the dog threw Mr Rehill around like a "rag doll".

"At first, the dog was trying to wake him up, licking him, but it became distressed when he didn't get up and started to bite him."