More than 100 detectives were scrutinizing why Derrick Bird, 52, decided to go on a three-hour shooting spree Wednesday in the northwestern county of Cumbria.
Some reports said Bird had argued with fellow cab drivers the night before the killings; others suggested a family dispute. But Cumbria police said the process of piecing together Bird's movements and ascertaining a motive is "a difficult and slow process" and urged patience.
The killing spree was Britain's deadliest mass shooting since 1996, and it jolted a country where handguns are banned and multiple shootings rare.
Police initially said 25 people had been wounded, but Home Secretary Theresa May said Thursday that 11 were treated in hospitals. Eight remained hospitalized Thursday, with three upgraded to serious condition from critical.
Police identified one of the victims as Kevin Commons, a lawyer who did work for Bird's family. The BBC and other media reported that Bird's twin brother, David, was among the fatalities.
The first shootings were reported Wednesday morning in the coastal town of Whitehaven, about 350 miles (560 kilometers) northwest of London. Police warned residents to stay indoors as they tracked the gunman's progress across the county.
Witnesses described seeing the gunman driving around shooting from the window of his car. Police said there were 30 separate crime scenes.
Bird's body was found in woods near Boot, a hamlet popular with hikers and vacationers in England's hilly, scenic Lake District. Police said two weapons, a shotgun and a .22-caliber rifle fitted with a telescopic sight, were recovered from the scene. Officials confirmed Bird held licenses for both weapons.
In Whitehaven, groups of residents gathered at the local market to remember those who died — and recount tales of near-misses.
Michael Murray, who is also a taxi driver, was standing near the front of cab stand when Bird, known affectionately as "Birdie," first approached.
"I saw 'Birdie' pull up beside me and he was waving a shotgun out of the window," Murray said. "I ducked to the floor before I could see if he was pointing at me.
"I always got on with Birdie, he had no grudges against me, I suppose that's what saved me. He was a sound guy and a private guy." June Lamb, a housewife, said she knew Bird "very well." "Derrick didn't mix with people very much," she said.
"He was very quiet, but not a loner as such. He would lark about with people." Prime Minister David Cameron offered condolences to "all those caught up in these tragic events, especially the families and friends of those killed or injured." Queen Elizabeth II said she shared in "the grief and horror of the whole country." May said she and the prime minister would visit the area on Friday.
Cameron's spokesman, Steve Field, declined to say whether the government would consider any review of Britain's stringent gun laws as a result of the killings.
"It is important that we find out the facts of the case before going into further detail," Field said. "The UK
gun laws are the toughest in the world. There are very strict rules operating at the moment." Rules on gun ownership were tightened after two massacres in the 1980s and 1990s. In 1987, gun enthusiast Michael Ryan killed 16 people in the English town of Hungerford. In 1996, Thomas Hamilton killed 16 children and a teacher at a primary school in Dunblane, Scotland.
In recent years, there have been fewer than 100 gun murders annually across Britain.
May told lawmakers that "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 that we shouldn't do everything we can to stop it happening again." J. Reid Meloy, a forensic psychologist and adjunct professor at the University of California, San Diego, said most mass killers have spent considerable time formulating their plan.
Though they are harboring murderous intent, they appear to be living their lives normally until the attack happens.
Often, friends or investigators will look back at the killer's final days and see a dropped hint about what was being planned.
"There's likely to be leakage, some communication to a third party about an intent to do this kind of killing," Meloy said. "But people who have access to the leakage tend to minimize it or deny it. It is such an unusual or abhorrent event, they don't believe the person is going to do it." Peter Leder, a taxi driver who knew Bird, said he had seen the gunman Tuesday and didn't notice anything that was obviously amiss. But he was struck by Bird's departing words.
"When he left he said, 'See you Peter, but I won't see you again,"' Leder told Channel 4 News.
