The beast is said to have savaged its owner and another person.
1
Both were taken to hospital for treatment while another dog injured by the hound needed to be seen by a vet.
Police have not confirmed the breed of the attacker but said it had been destroyed.
A woman has also been arrested over Monday’s incident in Halifax, West Yorks.
One local, who wanted to remain anonymous, saw officers with “guns drawn at the dog”, which was hiding next to a shed.
read more on xl bully dogs
He said: “We had armed police and a helicopter searchlight.
“Police knocked on doors and windows, telling everyone to stay inside.
“Next, I saw them in my neighbour’s garden with guns drawn at the dog, which was trying to hide between a shed and a fence.
“They shot it twice, I think.”
A West Yorkshire Police spokesman said: “Attempts to restrain the dog were unsuccessful and it was destroyed by armed officers.
“Enquiries are ongoing to establish the exact circumstances of what happened.”