Gunman Raoul Moat's final moments remain a mystery, an inquest heard today.
Although Moat was hit by police Tasers, it was unclear if officers fired before or after the father-of-three shot himself in the head, a police investigator said.
However Steve Reynolds, of the Independent Police Complaints Commission (IPCC), told the hearing two Tasers were fired at the steroid-addicted former nightclub doorman in an "effort to stop him taking his own life".
Armed police fired Tasers at Moat, 37, that were not approved by the Home Office, the inquest at Newcastle Civic Centre also heard.
The XRep Taser, which is fired from a 12-gauge shotgun, is currently being tested by the Home Office before being approved for use by police forces in England and Wales.
But the Home Office stressed police could use any weapon they saw fit as long as its use was "lawful, reasonable and proportionate".
Mr Reynolds said that at 7.25pm on Friday a member of the public saw Moat at the Riverside park area in Rothbury, Northumberland, and called police.
"Armed Police contained Mr Moat and negotiators were deployed hoping to achieve a peaceful outcome," he said.
"He was in possession of a sawn-off shotgun which he had pointed at his head.
"At 1.12am on July 10 Mr Moat's shotgun discharged resulting in him receiving fatal injuries.
"At some point around the time of the fatal shot two West Yorkshire Police firearms officers armed with XRep Tasers discharged their weapons at Mr Moat.
"This is understood to have been in an effort to prevent Mr Moat taking his own life.
"At this stage the precise sequence of events regarding the discharge of the Tasers has not been established and is under investigation."
Mr Reynolds said the matter had been referred to the IPCC by Northumbria Police.
He would be focusing his investigation on the final hours of Moat's life - from when he was first spotted at 7.25pm until he was formally declared dead in hospital at 2.22am the following day - and looking at the tactics the police used.
Moat went on the run after killing his his ex-girlfriend Samantha Stobbart's new lover Chris Brown, 29, and seriously injuring her.
The next day Moat blasted unsuspecting police office David Rathband, 42, and fled. A huge manhunt was launched leading to Moat's last stand in the early hours of Saturday morning.
Mr Reynolds said he would also be investigating how police had handled intelligence from Durham Prison warning that Moat would harm his Miss Stobbart.
"The IPCC investigation will also investigate the command strategy and tactics employed by the police and review all records in order to ascertain what steps were taken to resolve the incident," he said.
"The review of tactics will consider the deployment and use of the XRep Taser."
Newcastle Coroner David Mitford said the preliminary cause of death was a gunshot wound to the head.
Moat was formally identified by his uncle, Charlie Alexander.
No family members were in court today as the coroner opened and adjourned the hearing until a later date.
The Home Office confirmed the XRep Taser was not approved for use by forces in England and Wales.
A spokesman said: "It is currently subject to testing by the HOSDB (Home Office Scientific Development Branch).
"However, legally, police forces have discretion to use any equipment they see fit as long as the use of force is lawful, reasonable and proportionate.
"The process for approval of less lethal weapons is set out in a Home Office code of practice document on police use of firearms which Chief Constables must 'have regard to'."
As the inquest opened three men were arrested for allegedly assisting the fugitive.
The men were held during raids in Newcastle and Gateshead.
A police spokesman said: "Three men have been arrested this morning in connection with assisting an offender during the search for Raoul Moat.
"The men were arrested from two addresses in Gateshead and one in Newcastle.
"At this stage the investigation is still on-going and further arrests can't be ruled out."
Today's arrests bring the total to 10 made so far in the investigation, police confirmed.
Northumbria Police also defended their investigation today claiming searches of the storm drain running under Rothbury had not found evidence that Moat had hidden there.
There had been suggestions that Moat had avoided detection during his week on-the-run by hiding in the drain.Reuse content