This has raised doubts over Incheon International Airport’s security system and the police and justice ministry as they failed to prevent his departure. This is not the first time a local sex offender wearing an ankle monitor has left the country.

Incheon International Airport has ranked among the top in the world for 12 consecutive years, due to its high-tech equipment and facilities.

But it was not enough to weed out the suspect through its state of the art security screening due to the lack of communication between airport, legal and law enforcement agencies.

Many are calling for the installation of a hotline between the justice ministry and airports to check if offenders have been given approval from the government for departure.

Under the current law, suspects with ankle monitors can only leave the country if approved by the Ministry of Justice.

Shin used these security loopholes to leave.

He was brought back and handed over to Seoul Nowon Police Station, where he was arrested for numerous charges including vandalising the ankle monitor and violating his probation.

Shin has also been under investigation for the use of narcotics.

He raped a woman in her 20’s at a motel in Gyeonggi Province after drugging her with Zolpidem, a drug that is primarily used for the treatment of sleep disorders.

Soon after the incident, prosecutors filed an arrest warrant for Shin as he is a repeat sex offender and has a record of cutting his ankle monitor off twice in the past.

But the warrant was rejected by the court.

“Shin’s whereabouts can be known as he was wearing an ankle monitor and was given the right to exercise defence,” the court said at the time.

The police also failed to file for a travel ban for Shin, and he was able to buy a plane ticket for Vietnam.

The metal detector at Incheon Airport’s security check point went off due to the ankle monitor.

The suspect then went through a separate closed door inspection where Shin lied to the airport security that his trip was approved by the government.

Without checking with the justice ministry, the airport security let him pass, even though it was aware Shin was a sex offender.

“If a travel ban is not issued, the airport security does not know if the sex offender got approval from the government,” said a justice ministry official.

Only after the plane took off and the global positioning system from the ankle bracelet became unavailable did a probation officer contact the Nowon Police Station.

Late last month, a sex offender in his 50s also left for Osaka, Japan through Gimpo International Airport.

The suspect has not been caught, and the justice ministry has requested Interpol to issue a red listing for him.