Better wait for another confirmation, their source is a Twitter user that claims:
Montenegrin police have detained a person suspected of being one of the most wanted fugitives, South Korean citizen Do Kwon, co-founder and CEO of Singapore-based Terraform Labs.
I find it a bit weird and stupid for him to use a European airport, despite not being part of the EU Montenegro has a ton of extradition treaties, and with him on the Interpol list, there is no chance they will not deport him. Pretty a stupid move, he should have fled to some south Asian country instead.