Three suspects were in court on Monday after their arrest at a South African airport for illegally transporting gold bars.

According to The Associated Press , three Madagascar nationals were traveling from Madagascar to Dubai via South Africa were stopped at O.R. Tambo International Airport in Johannesburg and searched by security guards.

Officers working the checkpoint noticed something suspicious in the carry-on bags belonging to the suspects and informed the police. When the luggage was opened, officials found around 162 pounds of gold bullion, worth an estimated $4.1 million.

“Upon questioning of the suspects and further inspection of their hand luggage, officials discovered the gold bars and some foreign currency,” said South African police spokeswoman Col. Athlenda Mathe told The AP.

Officials familiar with the case said the suspects provided certification papers for the gold, which authorities are working to verify. Police in Johannesburg have also called on Interpol to determine the origin and destination of the gold bars.

In addition, South African authorities are investigating the incident as part of a possible international gold smuggling syndicate. Mathe claims “there is a possibility that money laundering and fraud charges will be brought against the three accused at a later stage.”

In October 2020, an airline passenger was arrested in India after being caught with more than two pounds of flattened gold hidden inside of his rectum .