Gunman Raoul Moat was "no psycho" and may have killed himself in an "involuntary reaction" to being Tasered by police, his brother has said.
Angus Moat is convinced he could have prevented his younger brother's death but said police would not let him intervene during the tense six-hour stand-off which ended with a fatal gunshot at 1.15am on Saturday.
The tax officer, 39, said his brother was a sensitive person who may have been suffering a breakdown when he shot his former girlfriend, killed her new boyfriend and then turned his gun on a police officer.
Mr Moat, of Newcastle, had not seen his brother for several years but immediately contacted police and offered to talk to him, only to be told it could make the situation "more volatile".
Mr Moat questioned why two electronic stun guns were used in the effort to bring Moat down and asked why no marks from the Tasers were mentioned in the post-mortem examination report, which gave his cause of death as a gunshot wound to the head.
He suggested the shock from the stun gun may have caused Moat to pull the trigger on the shotgun that he had been holding to his head throughout the stand-off.
The manhunt was sparked on July 3 after Moat's former girlfriend Sam Stobbart, 22, was shot and her 29-year-old boyfriend Chris Brown killed in Gateshead.