BANGKOK >>  Airport officials in Thailand say they followed proper security measures and gave no special treatment to Bangkok’s former police chief who was arrested earlier this week in Tokyo with a loaded gun in his luggage.

Lt. Gen. Comronwit Thoopgrajank was arrested Monday at Tokyo’s Narita International Airport on his way back to Bangkok with a handgun containing five bullets in his check-in luggage, according to a police official at Narita who spoke on condition of anonymity because of investigative policy.

The official said the gun was detected by X-ray check after it passed the airline check-in counter. Comronwit had in the meantime obtained his boarding pass and gone to the gate, where police brought his suitcase and opened it in his presence. Comronwit confirmed the contents were his, said the official.

The official said Comronwit’s explanation was that he had forgotten the gun was in his suitcase.

Comronwit was Bangkok’s police chief from 2012 to 2014 and then retired. His arrest has been front-page news in Thailand as questions swirled over whether he got a gun past airport security at Bangkok’s Suvarnabhumi Airport or if he obtained in Japan and why.

It also directed an unwanted spotlight on Thailand’s aviation sector, coming shortly after the U.N. body regulating world air traffic said Thailand had failed to meet a deadline for addressing safety concerns about oversight of its airlines. The International Civil Aviation Organization said its concern was focused on Thailand’s ability to conduct air operator certifications, and placed it on a list of countries whose aviation authorities fall short of international standards.

Suvarnabhumi officials called a news conference Thursday to deny any breach in security. They showed a detailed slideshow of screenshots from CCTV footage showing Comronwit entering the airport and going through security, removing his shoes and getting two carry-on bags checked by security scanners.

"The findings can confirm that no guns or ammunition were found" in the carry-ons or on the retired officer himself, said Suvarnabhumi Airport General Manager Sirote Duangratana. He said a printout of a security report from his checked-in baggage "showed that it was cleared and the luggage did not have any hazardous material."

"Our system meets the standards that are being used worldwide," said Sirote, adding that Comronwit was not given any special treatment. High-ranking police officers in Thailand are customarily given VIP treatment.

In Japan, carrying a gun is illegal except for police and others licensed for hunting and other limited purposes. Violators can face up to 10 years in prison.

Comronwit was handed over to prosecutors on Wednesday. Under Japanese law, prosecutors have up to 23 days to decide whether to press charges.