A bodyguard of Namal had gone close to the president with a concealed pistol.
The suspect is a corporal of the Army commando regiment, which also raises the question of Namal having an Army commando as a bodyguard, because the police have the responsibility of protecting MPs.
Namal’s driver too, is from the Army.
The CID is also investigating as to why the suspect was freed by PSD officials soon after his arrest following the breach of the president’s security.
Police spokesman ASP Ruwan Gunasekara said no armed persons are allowed to be at rallies attended by the president.
When contacted, Namal said he got to know about the incident only through media reports.
He said he spoke to the president about it and was told an investigation would take place.
Namal said he was yet to be questioned over the incident.