Police officials knew that Jake Davison, who went on to carry out a mass shooting in Plymouth, had a history of violent behaviour and possible mental health issues when they gave him a shotgun licence, a court has heard.
Davison applied for a certificate when he was 18, four years before the Keyham tragedy, and a check was carried out through Devon and Cornwall police's database.
The check revealed that Davison had assaulted two teachers at school, putting one in a headlock and headbutting and spitting on another, at the age of 12.
The following year he punched a fellow pupil in the face. These incidents were dealt with by "restorative justice" and did not count as a criminal record.
A report at the time stated Davison admitted he had "blown his top and taken his anger out on the wrong people".
Jurors at the inquest also heard that Davison's mother sought help for his "possible mental health issues" when he was in school.
These factors should have led police to class him as "very high" risk to own a shotgun, using their own "risk matrix".
But when his application was reviewed by David Rees, a firearms enquiry officer, he was rated as "very low risk".
Mr Rees wrote a report stating Davison was "fit and well" and planned to use a gun to go clay pigeon shooting with his uncle.
The report was sent to a senior officer who approved the application.
Less than four years later, Davison used his pump action shotgun to kill five people on the streets of Keyham.
Asked why he did not take the school assaults into account, Mr Rees said: "These were historical. They were committed at age 12 and 13.
"I didn’t feel I was required to consider these in the process of completing the application, so I didn’t.
"It was dealt with internally by the school and recorded as community resolution. These were not considered by me as part of the application."
Bridget Dolan KC, counsel to the inquest, asked: "What about the information from 2010 about 'ongoing possible mental health issues which his mother is referring to the GP?’
"Should that not have led you to think on the risk matrix to think this has potential to affect public safety?"
Mr Rees replied: "Yes."
Davison told Mr Rees he wanted to go clay pigeon shooting, and that he was not on any prescribed medication.
Ms Dolan asked: "Do you always take the word of the person who says they want to shoot clays? Is there any question as to whether the person is lying to you or not?"
He replied: "You do take their word. There is no investigation. It was the answer he gave so I accepted it."
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