A man has been arrested after an 83-year-old died from an attack by a pitbull-type dog.
Leslie Trotman was in his back garden when the dog escaped from a neighbour's home and attacked him.
The pensioner was badly bitten on his right leg when the dog struck on January 23. He suffered more injuries when the dog knocked him over.
He was taken to hospital and released later that day - but his son found him dead in his home on January 29.
Scotland Yard confirmed the dog had escaped from a neighbour's garden in Brentford, west London.
A man in his 30s has been arrested on suspicion of manslaughter.
The manslaughter inquiries began after a post-mortem examination revealed Mr Trotman died from a haemorrhage caused by a ruptured spleen.
A police spokesman said: "Officers believe these injuries were sustained during the attack by the dog."
It is not clear how the animal managed to escape and enter Mr Trotman's property.
Police have released the suspect on bail and seized three dogs from an address in Rowan Road.
Scotland Yard is asking anyone with information to contact them on 020 8721 4054 or call Crimestoppers anonymously on 0800 555 111 .