West Yorkshire Police said the man, who has not been named, was out walking with his Yorkshire terrier in Huddersfield on Monday when he was attacked by another dog. He died later in hospital.
The incident has been referred to the Independent Police Complaints Commission because the dog involved in the attack was seized by officers earlier this month but returned to its owner after it was determined it was not a banned breed.
A woman who said she was the victim’s cousin wrote on Facebook: “There was nothing accidental about this, it was a tragic incident that should never have happened and correct measures were not taken to ensure this situation wouldn’t arise.
“We hope that in the coming days, a true representation of what happened yesterday will come to light and end all speculation. At this point, there is nothing to gain from finger pointing or blaming of dangerous dogs or their owners.”
A 29-year-old man, the owner of the dog, was arrested in connection with the incident and later released on police bail.
Detective Chief Inspector Mark Swift said: “Clearly our thoughts go out to the family at this tragic time. They are understandably devastated by what has happened and are being supported by specially trained officers.
“Our investigation is continuing. We believe that the victim was out with his own dog at the time of the attack near to his home. His dog, a Yorkshire terrier, was also injured during the incident and received emergency veterinary care.”
He said the suspect dog was captured and taken to kennels.
Jamie Hanson, 24, a neighbour of the victim, told reporters: “The guy just ended up passing out. He was unconscious, the poor guy. When the police came an officer used a fire extinguisher from the car to get the dog off.”