Derrick Bird, who shot dead 12 people in Cumbria, held a firearms licence for 20 years, it has emerged.
Cumbria Police said the taxi driver had a shotgun certificate and a firearms licence for weapons, and he is understood to have been a licensed firearms holder since the age of 32.
Deputy Chief Constable Stuart Hyde said the two weapons they had recovered from Bird, a shotgun and a rifle, appeared similar to those described on the licences, but that officers would need to perform a detailed forensic examination to confirm this.
The UK has some of the toughest gun control laws in the world. If you want to own a gun, it is very difficult to do so.
In the United States, you can declare that it is your constitutional right to bear arms. But in the UK, you need to spend hours filling in paperwork and proving to police officers that you are not a danger to society.
The system is administered by police forces in each part of the UK and in England, Scotland and Wales there are separate licences for shotguns and for other firearms.