Derrick Bird's shooting spree across Cumbria yesterday, which left 12 people dead, has prompted a debate on the effectiveness of Britain's gun laws.
Police have revealed that the 52-year-old had been a licensed firearms holder for the last 20 years. Home secretary Theresa May confirmed the license covered both the shotgun and .22 rifle fitted with a telescopic sight used by the killer.
Ms May told the Commons it was important to wait until the police's investigation into the mass killing before making any major changes to gun laws.
"Mass killings as we saw yesterday are fortunately extremely rare in our country. But that doesn't make it any the less painful and it doesn't mean we shouldn't do everything we can to stop it happening again," she said.
"When there are lessons to be learned we will learn them, and when there are changes to be made we will make them."
Later, David Cameron insistsed there would be no "knee-jerk reaction" to the law because of the killings.
But local MP Jamie Reed, who appeared shell-shocked by events during an interview with Radio 5 Live yesterday, said gun control needed to be looked at again.
"I don't think my place is in the House of Commons right now, I think it's up here doing whatever I can do," he said.
"I think we need to learn the lessons of this event first, then I think it's right that we look at gun control in light of this."
Vince Cable, business secretary, and Keith Vaz, former chair of the home affairs select committee, urged caution before people started jumping to conclusions.
"I think it's very important that we don't rush into any conclusions about policy until we're clear about what happened," Dr Cable told the BBC this morning.
"It's not clear that the existing system hasn't worked; that's a matter for investigation."
Mr Vaz told Newsnight: "I think it's difficult...we don't have all the facts.
"I think we ought to wait for a definitive statement before deciding if the law is in any way at fault."
No 10 defended gun laws in the UK, with the prime minister's spokesman saying they were the "toughest in the world".
The British Association for Shooting and Conservation (BASC) sent out a statement in the aftermath of the attacks expressing sympathy for those affected by the shootings.
"The events. in Cumbria are tragic and shocking, and as representatives of Britain's lawful gun owners BASC would like to make clear its deeply felt sorrow at these events which will have long-lasting repercussions within the affected families and communities," the statement read.
Twelve people died and 11 were injured yesterday during the killing spree, which is thought to have involved a row with fellow tax drivers and the settling of certain long-running family disputes.
The first two people Bird killed were reported to be his twin brother David and family solicitor Kevin Commons, who was in charge of his mother's will. Police are continuing to confirm the identity of those who died as their investigation continues.
Home secretary Ms May and prime minister David Cameron will visit Cumbria tomorrow. The Home Office may provide extra funding for Cumbria police, while the Department for Communities and Local Government is seeking to establish what "support and assistance" it can give to local authorities.
Cumbria police faced its most challenging day ever yesterday and relied on assistance from other constabularies to cope with the crisis.
"It is a force that has very low levels of crime and a largely rural area," Ms May added.
"But I'm confident that support has been provided from other neighbouring forces where they are able to help. That will be ongoing."