Suvarnabhumi airport's security procedures should be examined to find out whether former metropolitan police chief Kamronwit Thoopkrachang was allowed to leave the country with an unchecked gun, Prime Minister Prayut Chan-o-cha said on Wednesday.
The prime minister said if Pol Lt Gen Kamronwit was allowed through with the weapon, an investigation must be carried out find out how that could happen.
"Was there any exception? Did he go through the X-ray machine for scanning? If something went wrong, it was wrong," he said.
Asked about assistance for Pol Lt Gen Kamronwit, Gen Prayut said he would be provided with lawyers. "He is no longer an official, but an ordinary person. No matter what, he will be taken care of," he added.
Pol Lt Gen Kamronwit was caught by Japanese authorities with a gun in his possession while about to leave Narita airport for Thailand on a June 22 flight.
The prime minister said everybody should bear in mind that the law is the law.
"Thai people should be taught to respect the law, not only of their own country but also of other countries.
"One may be able to do anything he wants to in Thailand, but not in other countries. When some people are in trouble abroad, it is the government they look to for help.
"The government has to help, otherwise it would be blamed for not taking care of its own people," Gen Prayut said.
Gen Prayut made this remark when asked whether the Kamronwit incident would affect Thailand's efforts to convince the International Civil Aviation Organisation (ICAO) its airport safety standards were adequate.
He said Pol Lt Gen Kamronwit's case was a personal offence and had nothing to do with the ICAO.
Deputy Prime Minister Prawit Wongsuwon said Pol Lt Gen Kamronwit's case was a reminder to security officials to make sure not to let illegal items slip out of the country.
"If an illegal item from Thailand was found in another country, it is Thailand that is to blame. Other countries would conceive that both our equipment and officials are bad," Gen Prawit said.
He said the government had ordered an investigation into the incident to prevent a recurrence.
Gen Prawit said he did not know whether Pol Lt Gen Karomwit got the gun in Japan or took it with him from Thailand. "If it was from Thailand, then our authorities would be to blame," he added.
"Everybody must be subject to security checks, without exception," he said.
Grp Capt Kanpat Mangkalasiri, vice president of the Airports of Thailand (AoT), said taking a gun on board a plane is allowed for domestic flights, but prohibited for international flights, except with a permit for it to be loaded as a package.
The AoT was investigating whether Pol Lt Gen Kamronwit's gun had passed through security procedures unchecked, and how.
A person is allowed to carry a weapon on board a plane only if on duty to provide security for a very important person, Grp Capt Kanpat said.