Killer Derrick Bird shot his semi-naked twin brother 11 times with a rifle after confronting him in his bedroom, the inquest into the deaths of his victims heard today.
Relatives of the dead held hands to their faces as the full horror of the taxi-driver's rampage through West Cumbria was revealed for the first time at the hearing.
During the killing spree on June 2 last year which left 12 dead, Bird, 52, carrying a 12-bore sawn-off shotgun and a .22 rifle, had repeatedly stopped his Citroen Picasso car, called victims over as if to ask the time, then simply blasted them in the face with a shotgun.
On more than one occasion he then left his vehicle, changed his weapon to the rifle, and finished off his injured victims by shooting them to the head at point blank range.
The details of the slaughter were given by Detective Chief Superintendent Iain Goulding, from Cumbria Police, the senior investigating officer.
His opening presentation to the inquest, lasting an hour and a half, was heard in silence by more than 100 observers at the Energus Centre in Workington.
They included relatives of Bird himself, families of the victims, police, lawyers and press.
Mr Goulding confirmed many of the motives believed to have sparked the killing spree.
They included an investigation by the taxman into unpaid income tax and insults from fellow taxi drivers over his personal hygiene and the cleanliness of his vehicle, the inquest heard.
The officer's presentation included still photos of the victims and the crime scenes and CCTV footage of the rampage on the day.
The hearing will analyse all 13 deaths in chronological order and is expected to last up to six weeks.
Bird, from Rowrah, also injured 11 others in his shooting spree in Lamplugh, Frizington, Whitehaven, Egremont, Gosforth and Seascale before he was found dead in a wooded area near Boot.
He had blasted himself in the head with the rifle.
Mr Goulding told the hearing Bird, who lived alone and was separated from the mother of his two grown-up children, had for "some time" been worried about the tax investigation and sought the help of his brother and Kevin Commons, the Bird family solicitor.
This led to increased contact between the brothers and to him ringing his brother David, no less than 44 times on May 30 alone.
They also met the next day and appeared to be having a "serious conversation" outside David's home in Lamplugh.
Mr Goulding added: "Derrick Bird appeared to have developed irrational fears about being imprisoned for the tax matters, made worse by the belief his brother and solicitor were conspiring against him."
A meeting had been planned between Mr Commons and Bird on the day of the killing spree at which Bird believed he would be arrested and "immediately go to prison".
The night before, Bird spoke to fellow taxi driver Peter Leder, telling him: "You won't see me again."
In the early hours of June 2 he left his own shabby terrace house in Rowrah, armed with the sawn-off shotgun and rifle.
Some of the ammunition he took was described as "subsonic hollow point" and designed to expand on impact, causing maximum damage.
Bird left his home in the early hours of June 2 and went to his twin's house.
"Evidence suggests he confronted his brother, semi-clothed, in bed. He fired at him repeatedly with the .22 rifle," Mr Goulding said.
David Bird was shot in the neck, face, head and back.
"A total of 11 spent cartridges were recovered at the scene, the maximum number of rounds the rifle would carry," the officer said.
David Bird's bullet-riddled body - he had suffered 15 different entry and exit wounds - was only found around 11am by a neighbour.
Bird was next spotted outside the house of Kevin Commons in Frizington at around 5.30am.
At around 10am the 60-year-old solicitor left his house in his vehicle, but his path on his driveway was blocked by Bird's Citroen Picasso.
Bird fired twice with his shotgun at Mr Commons, hitting him once in the shoulder.
Witnesses told police the injured man scrambled out of the vehicle and ran back to his house, pursued by Bird.
Mr Commons was found dead with two .22 rifle wounds to the head.
Bird drove away and police were called to what was then believed to be an incident involving an air rifle.
At 10.14 Bird called at the house of Neil Jacques to try to get his hands on a "more modern, accurate, self-ejecting" shotgun he had sold to Mr Jacques the previous night, but he was not at home.
Bird next headed for the taxi rank on Duke Street in Whitehaven where he had worked as a self-employed cabbie.
It was here, Mr Goulding said, that he had been in dispute on a number of occasions with fellow taxi drivers and ridiculed about his "personal hygiene and the cleanliness of his taxi".
It is thought the tyres of his vehicle had been damaged on at least one occasion.
Around 10.25am he spotted his third fatal victim, fellow taxi driver Darren Rewcastle, at a sandwich shop.
"Derrick Bird called Darren over to his taxi," Mr Goulding continued.
"Darren bent down to speak to him. At this point Derrick Bird opened fire with the shotgun hitting Darren at close range to the lower face and neck."
Mr Rewcastle, 43, was also then shot a second time to the stomach at close range, the inquest heard.
Bird then drove around the town's one-way system before arriving back at the taxi rank, where he shot Donald Reid in the back.
As Mr Reid crawled along the pavement to get away, Bird got out of his car, followed and raised his weapon as if to fire again but was shouted at by another taxi driver, stopped and got back in his vehicle.
Again he drove past the taxi rank and fired two more shots before driving away, this time followed by Pc Mick Taylor, in a car driven by a member of the public, Paul Goodwin.
At 10.31am Bird stopped on Scotch Street, where he called fellow taxi driver Paul Wilson over to his car.
Mr Wilson bent down to speak into the passenger window and Bird opened fire with the shotgun, hitting his victim in the face.
Mr Wilson survived and was able to tell police the identity of the gunman.
Two minutes later he drove past the taxi of Terence Kennedy, carrying passenger Emma Percival.
Bird "smiled" at Mr Kennedy, who he knew, then opened fire with the shotgun.
Mr Kennedy survived but had to have a portion of his right lower arm amputated. His passenger was slightly injured.
Bird was then spotted by two officers in a police van, but he pointed the gun at them and they dived below the dashboard, while he drove off, and they lost him.
At 10.50am Susan Hughes, 57, a mother-of-two was carrying her shopping to her home in Egremont.
Bird stopped his car alongside Mrs Hughes and blasted her with the shotgun to the left breast and abdomen. He then also shot her in the head with his .22 rifle.
Three minutes later he pulled up alongside Kenneth Fishburn, 71, who shot at close range with the shotgun. Mr Fishburn was killed instantly.
Bird reloaded, drove a short distance and called over Leslie Hunter to his car, where he delivered a "glancing" shot to the head of his victim.
Mr Hunter was then shot again in the back but survived.
As Bird left Egremont he spotted 15-year-old schoolgirl, Ashleigh Glaister and again called her over to his car.
But as she bent down to speak to him, she spotted one of the guns and ducked below the window as Bird pulled the trigger.
He missed her and she fled, with Bird reversing his car in chase, but then driving off at speed.
By 11.02am Bird was driving down a single-track road where he came across Isaac Dixon, 65, who he shot with the shotgun twice at close range, to the chest and hip.
At 11.07am Bird arrived at the house of Jason Carey in the village of Wilton.
Mr Carey was involved with the Solway Sub-Aqua Club, where Bird was a member and where he had fallen out with the committee.
Bird sounded his horn but Mr Carey, having worked a night shift, was in bed and did not answer.
By the time his wife Deborah got to the door, Bird was already driving off.
Mr Goulding, continuing the narrative, told the hearing Bird next came across Jennifer Jackson in the village.
He stopped his car alongside the 68-year-old and shot her once in the chest with the shotgun and twice in the head with the .22 rifle.
Moments later Mr Goulding said Bird then "coincidentally" came across James Jackson, 67, Mrs Jackson's husband, talking to Christine Hunter-Hall.
Bird pointed the shotgun out of the driver's window and shot Mr Jackson in the forehead, killing him instantly.
Ms Hunter-Hall was hit in the back, suffering "extensive injuries" but surviving.
Around 11.18am local farmer and amateur rugby league player, Garry Purdham was working on the edge of a field just outside Gosforth.
Bird was seen by a witness to pull up alongside the 31-year-old father-of-two, then shoot him twice with the shotgun. He went on to shoot his victim twice more with the .22 rifle.
Around 11.25am Bird's car was seen parked near to Drigg Road outside Seascale.
Jamie Clark, 23, the youngest victim, was driving back to Seascale along the road.
Mr Clark's Smart Car was later found on its side, the wheels still turning, with the victim killed by Bird, blasted to the right side of his head with the shotgun.
Two minutes later Bird was in Seascale, driving under a narrow rail bridge. He forced Harry Berger to reverse in his Land Rover prompting Mr Berger to "mouth" a comment to Bird.
Bird responded by opening fire, hitting Mr Berger in the hand and shoulder - but he survived.
The gunman then re-loaded and moments later drove up behind Michael Pike, 64, who was taking his morning bicycle ride.
Bird drove alongside Mr Pike and opened fire. The first shot missed but the second hit the victim in the head, killing him instantly.
Just a few hundred yards up the road he came across elderly spinster Jane Robinson, 66, who was out delivering homeware catalogues.
Witnesses told police Bird "caused" Ms Robinson to lean in through the passenger window.
He then opened fire with the shotgun and Ms Robinson was, "flung back" from the impact, being killed instantly.