A Chinese tourist and a woman from Myanmar were killed at Siam Paragon shopping mall in Bangkok on Tuesday afternoon, by a teenager using a modified BB gun, according to Pol Gen Torsak Sukvimol, the national police chief.

Five other people were also injured, three of whom are being treated at Chulalongkorn Hospital, with two in a serious condition. Their Majesties the King and Queen have placed them under Royal patronage. The two others are being treated at the Police General and Bangkok Christian hospitals.

Pol Gen Torsak told the media late Tuesday night said that the suspected gunman did not speak coherently, because he has a mental problem for which he has received treatment at Rajavithi Hospital, but had lately not been taking the medication prescribed by his doctor. The suspect appears to suffer from hallucinations.

He said that police investigators are trying to determine the motive for the shooting and his actual age, adding that, at this stage, he could not provide more details about the suspect or his family.

Police later searched the house where the suspect has been living and found more ammunition of various calibres, a few paper targets and another BB pistol. Material found on his cell phone shows the suspect training on the use of firearms.

According to the police report, the suspect dressed in a tactical style, wearing black mountain-climbing shoes, a grey cap and a black jacket. The shooting started on the mezzanine floor of the mall and continued as the suspect moved to the second and third floors, before surrendering to police.

President of the Association of Thai Travel Agents, Sisdivachr Cheewarattanaporn, said that the shooting will definitely affect tourism because many Chinese people already have doubts over their safety in Thailand.