Croatian and Slovenian investigators are searching six locations in Zagreb and Zadar as well as 12 in Maribor and Celje as part of a joint investigation into corruption in KBM Projekt, a company the NKBM set up in Croatia.
The Croatian Police Directorate told Hina their Slovenian colleagues had requested assistance.
According to Slovenian media, investigators are looking into the bank's operations through the fictitious companies it set up in Croatia which, between 2006 and 2009, bought for the NKMB real estate at too high prices, defrauding Slovenia's second largest state-owned bank of about EUR 60 million.
According to the media, the corruption also allegedly enabled a company to try to buy the Slovenian newspaper Vecer, probably to siphon money out of it too.
Slovenian media speculate the police are trying to find out if any Croatian citizens who received about EUR 60 million from KBM Projekt for shares in those companies had accounts in the NKBM.
Slovenia's anti-corruption office has announced an investigation into bank executives involved in the financing of a private company which last year tried to buy the Vecer daily.