Footage shows what appears to be the suspect of a shooting at a Bangkok shopping mall practising at a firing range just days before the incident took place.

A 14-year-old suspect was arrested after two people were shot dead and five injured at the Siam Paragon Centre on October 3.

Derick Moo, the shocked tourist who photographed what appears to be the 14-year-old at the Shooting Range Territorial Defense Department, said: "When I saw the gunman in Bangkok, I recalled that the person I met at the shooting range shot at least a hundred bullets that day.

"I can't imagine that he was 14 years old. I feel so lucky when I think about it.

"I was taking pictures of myself and he just happened to be in the background."

Police searched the room of the alleged gunman on Tuesday night and found unused bullets and shooting targets.

Police Chief General Torsak Sukvimol said the suspect will undergo hospital checks this week to assess his psychological state.

The youngster is facing charges of murder, attempted murder, possessing a gun without permission, carrying firearms in public and firing a gun in public.

The suspect of a shooting at a Bangkok shopping mall is practising at a firing range just days before the incident took place.

Phasid Trutassanawin, 14, was pictured in the same U.S. flag baseball cap and dark-rimmed glasses while holding a .22 revolver at the facility in Bangkok, Thailand, last week.

He went on to kill at least two people and injure five others during a shooting spree at the upmarket Siam Paragon centre in the capital on Tuesday afternoon shortly after 4pm local time.

The former outstanding pupil - who had won awards for his academic excellence - was pinned to the ground and arrested as terrified shoppers fled for their lives. Four people are in intensive care.

Derick Moo, the shocked tourist who photographed Phasid at the Shooting Range Territorial Defense Department, said: 'When I saw the gunman in Bangkok, I recalled that the person I met at the shooting range shot at least a hundred bullets that day.

'I can't imagine that he was 14 years old. I feel so lucky when I think about it.

‘I was taking pictures of myself and he just happened to be in the background.'

Police searched the room of the alleged gunman on Tuesday night and found unused bullets and shooting targets.

Phasid's shocked teachers from an expensive private school called The Essence said they were devastated by the incident.

Headteacher Wiwat Kitthamani said: ‘The Essence expresses its deepest condolences to the families of those who died and those injured in the shooting incident.

‘The Essence was informed that the perpetrator was a student here. We recognise that this incident has had an impact on all parties involved.

‘We will cooperate with all employees and would like to ask for sympathy from everyone.

‘Please respect the privacy of the family of the young person who caused the incident, who is also a child and youth. And if the parents and students are uncomfortable with the incident, or want to meet me to talk, I am ready to meet everyone.'

Police Chief General Torsak Sukvimol said the suspect will undergo hospital checks this week to assess his psychological state.

The youngster is facing charges of murder, attempted murder, possessing a gun without permission, carrying firearms in public and firing a gun in public.