London, England (CNN) -- The twin brother of the man allegedly responsible for one of the worst massacres in recent British history was among 12 people killed before the gunman took his own life, police said Thursday. The series of drive-by shootings in northern England also left 11 people wounded.
David Bird, the 52-year-old twin brother of alleged shooter Derrick Bird, was found dead at his home in the English village of Lamplugh, police said. David Bird, they noted, was the father of three daughters.
Early Wednesday evening, British authorities identified four other victims.
Garry John Purdham, 31, was found dead in a field on the roadside next to a pub. Darren Paul Rewcastle, 43, was a local taxi driver. Cyclist Michael James Pike, 64, was shot dead in the road. Jamie Michael Dennis Clark, 23, was found dead in his car.
Earlier, authorities named three other people killed in the shootings: 60-year-old solicitor Kevin Commons, who was found in his driveway; 57-year-old Susan Hughes, a mother of two; and 66-year-old Jane Elizabeth Robinson.
The UK's head of state, Queen Elizabeth II, issued condolences, saying she was "deeply shocked" by what happened.
"In asking you to pass my deepest and most heartfelt sympathy to the families of all those who were killed or injured, and to the injured themselves, I am sure I share in the grief and horror of the whole country," the queen said.
Police also released a map tracing the route that suspect Derrick Bird, 52, is believed to have traveled on his rampage through the region on Wednesday.
The route begins near the village of Lamplugh and winds through Cumbria, taking in the seaside towns of Whitehaven and Seascale before ending up farther inland near Boot, in the Lake District.
Police lifted the cordons at most of the 30 separate crime scenes, but Derrick Bird's house in Rowrah, near Frizington, remained one of those roped off, they said.
Forensic experts were examining two weapons seized by police, a shotgun and a .22 rifle fitted with a telescopic sight. Police said Bird was a licensed firearms holder for 20 years and they were investigating whether the license covers the seized firearms.
"The focus of the 100-strong squad of detectives investigating the incident is firmly on finding out why someone would want to take so many lives in such a short space of time," Cumbria Police said in a statement. "Officers and staff are conducting forensic evidential searches and tests across the area at each location."
"What happened [on Wednesday] was unthinkable and is without doubt the most horrific incident I have seen in my 25 year long policing career," said Cumbria Chief Constable Craig Mackey. "We now need to work together as a county to recover as we look to the future."
Police finished searching the known and possible routes Bird could have used -- an area covering 150 kilometers (93 miles) -- and said as a result they were not expecting to find any more victims.
Of the wounded, eight remained in hospitals Thursday, with four in stable and four in "comfortable" condition, police said.
Local Detective Chief Superintendent Iain Goulding released a statement identifying Derrick Bird as a self-employed taxi driver who had lived in Rowrah since 1993. Goulding noted that Bird drove a silver Citroen Picasso, which was used during Wednesday's shooting spree.
Meanwhile, a taxi driver shot in the back during Wednesday's killing spree has described how he watched Bird shoot dead another driver, Darren Rewcastle, at point blank range.
"He turned up and shouted 'Darren' before walking up to him and taking his face off. I saw it. He just shot him," Reed, a former soldier, told the Liverpool Echo.
Peter Leder, who described himself as a friend of Bird's, told CNN he spoke to Bird on Tuesday night and Bird told him, "You won't see me again."
Leder said Bird drove his taxi in Whitehaven for more than 20 years and described him as "an outgoing, well-known guy, who everyone liked."
Bird was close to his mother, who is ill in a local nursing home, Leder said.
He said his friend enjoyed scuba diving, went on several diving trips abroad and practiced regularly at the Whitehaven swimming baths. Leder said he knew Bird had guns but said he was not violent.
"I can't shed any light on it," Leder said. "... He was a decent guy, and I'm sorry for what's happened."
CNN's David Wilkinson and Alan Silverleib contributed to this report.