Gunman Raoul Moat may have shot himself twice in the head, the inquest into his death has heard.
A police negotiator said he heard what he thought was two shots, before the former doorman's head "fell back".
He described himself as "in the zone" - concentrating on Moat - and was not aware of any Tasers being fired during the stand-off in Rothbury.
The inquest was also told Moat felt like King Kong or the Incredible Hulk while on the run from the police.
The negotiator said that he heard a sound like shotgun, followed by what he believed to be was Moat screaming out with pain, possibly because the cartridge had grazed or missed him.
After a second "pop" he saw Moat's head go back, leading him to believe he had shot himself twice in the head.
Earlier, a recording the former doorman had made during the manhunt was played, in which he said he hated himself.
The jury was told he was paranoid, suspicious, mistrustful of authority and blamed others for his misfortune.
These feelings could have been the result of a traumatic childhood, in which he was beaten and once saw his mother burn all his toys, it was said.
Moat himself had said an expert had suggested his feelings could be linked to rejection from his mother but said he didn't understand "that kind of thing".
But according to a forensic psychologist brought in to advise negotiators during a stand-off with armed police, Moat was not mentally ill.
Moat had gone on the run after critically injuring his ex-partner, Samantha Stobbart, killing her new boyfriend, Chris Brown, and shooting PC David Rathband in the face, blinding him.
He eventually died in Rothbury, Northumberland, after the stand-off.
In the recording made on a portable dictation device, Moat said: "I feel like King Kong when he's right at the top of that building, all messed up, when he's in a real mess.
"I hate myself. I do hate myself.
"It is a part of me. I'm like the Incredible Hulk.
"It is not anger, it is something completely different. It is just like a wild animal and it's been there all my life."
He added that he was not sure whether his parents had "put it there" or if it had "always been there".
"A psychologist said it has got something to do with my mother and rejection", he said.
"I don't know, I don't understand that kind of thing."
The jury heard from forensic psychologist John Hughes, who had prepared a psychological assessment based on letters seized from Moat's home and the telephone calls and recordings he made while on the run.
Mr Hughes said: "He feels like there is a huge, terrible, angry person in there.
"I did not interpret it to mean in a bigger picture there was any mental illness at that point.
"If you look at his behaviour as a whole there is not the sort of chaotic disorder and failure to plan there would be if he was mentally ill."
A letter written by a psychologist to Moat's doctor following an assessment in 2006 described Moat as saying he felt "jumpy all the time".
It added: "He has concealed an axe and a crossbow in his bedroom, he worries people may break in."
The inquest, at Newcastle Crown Court, is expected to last for a further three weeks.