Kwon reportedly flew from South Korea to Singapore ahead of the company’s crash in May last year.
In September, Seoul prosecutors requested that Interpol place him on the red notice list across the agency’s 195 member nations, and also revoked his passport.
But questions about his whereabouts intensified after the Singapore Police Force said that he was not in the country.
Montenegro authorities said Thursday that Kwon had “used falsified travel documents from Costa Rica” during passport control for a flight to Dubai.
Inspection of their luggage also found travel documents from Belgium and South Korea, while Interpol checks discovered that Belgian documents were forged, Montenegro’s interior ministry added.
Many investors lost their life savings when Kwon’s Luna and Terra entered a death spiral, and South Korean authorities have opened multiple criminal probes into the crash.
South Korea’s National Police Agency said it would collaborate with the country’s prosecutors as they seek Kwon’s extradition.
“As an organisation that works closely with the Interpol, we will actively cooperate with the Seoul Southern District Prosecutors’ Office,” Jeong Beom-seok, an official from the National Police Agency, told AFP.
Cryptocurrencies have come under increasing scrutiny from regulators across the globe following a string of recent controversies, including the high-profile collapse of the exchange FTX.
Kwon is accused of “orchestrating a multi-billion-dollar crypto asset securities fraud”, according to the US Securities and Exchange Commission.