The detective who investigated the assault of an innocent 16-year-old boy by Jake Davison did not know he had a legally held shotgun, an inquest heard.

Detective Constable Pablo Beckhurst was investigating the attack and had seen Davison had the “FC” marker on the police national computer, but did not know that it meant he held a firearms certificate.

The confusion meant staff in Devon and Cornwall Police’s firearms licensing unit were not told of the September 2020 assault until the following November and only after he had been placed on a restorative justice programme.

Det Con Beckhurst told the inquest in Exeter: “I was unfamiliar with the warning marker, FC, and my obligations in the policy to take action on it.

“I wouldn’t have known what the consequences of that were. I first learnt of the FC marker and what were my obligations were as a result of this incident.

“I spoke to other colleagues of mine, some who were senior, who had not known of the policy.”

The court heard Davison reigned down a volley of punches on the boy in a Plymouth skatepark after he was called a “fat c***” by another teenager.

The boy who insulted Davison ran off and the 22-year-old responded with a burst of violence so extreme his victim suffered injuries to his eyebrow, nose and lip.

CCTV of the incident shows him unleashing between seven and nine blows during the assault.

He approached the boy, who was sat on a wall, and yanked him off it and started hitting him – giving him no chance to defend himself.

As the boy goes limp, Davison continued the punches before the footage shows him picking him up and throwing him to the ground.

Davison then swings a punch at another boy and misses, and when a 15-year-old girl went to her friend’s aid she was slapped by Davison.

He then appears to either stumble over the teenager or kick him as he was on the floor as he left the scene.

The boy was taken to hospital by his mother where he received stitches to a cut above his eyebrow and was off college for at least five days due to swelling to his face.

In a police statement, the boy said he was unable to recall much of the incident having been told by friends he had been knocked out.

“All I remember is a man shouting ‘Oi’,” he said.

“I then found myself in the seated position and people telling me I had been assaulted and knocked out. I may have lost consciousness.

“The incident only lasted a few moments, and I don’t know the male that assaulted me.”

An initial crime report was taken by uniformed officers attending the scene, and after receiving information about the boy’s injuries the incident was later reclassified from common assault to assault occasioning actual bodily harm.

Bridget Dolan KC, counsel to the inquest, suggested the attack was “ferocious and intense”, and Det Con Beckhurst replied: “It’s unpleasant – it’s not words I would use when I viewed it.”

The officer said police could charge Davison with battery or assault occasioning actual bodily harm.

But they required authorisation from the Crown Prosecution Service if considering a charge of assault occasioning grievous bodily harm.

Det Con Beckhurst said the decision to refer Davison to the Pathfinder scheme was taken by his supervisor, a detective sergeant.

The inquest has previously heard Davison was so angry following the incident he wanted to kill the teenagers and went home to get his shotgun.

His legally held shotgun and certificate were later seized after a member of the Pathfinder scheme warned the force he was a licence holder but they were later returned in July 2021.

Just weeks later Davison killed his mother Maxine, 51, three-year-old Sophie Martyn, her father, Lee, 43, Stephen Washington, 59, and Kate Shepherd, 66.

Dominic Adamson KC, representing the families of the victims, suggested to Det Con Beckhurst that had he known what the “FC” marker meant Davison’s licence and weapon would have been seized immediately.

The officer replied: “Had I been aware of the policy…”

The inquest was adjourned until Monday.