The investigation into the Rs. 13.2 billion fraud at the National Development Bank (NDB) has taken an international dimension, with the Criminal Investigation Department requesting assistance from Interpol’s headquarters in Lyon, France.

A team of Interpol experts specialising in virtual currency investigations is scheduled to arrive in Sri Lanka to assist the probe, police said on Sunday. The involvement of cryptocurrency specialists suggests the stolen funds may have been routed through digital currency channels — a significant new detail in what has become one of Sri Lanka’s largest banking frauds.

Four suspects have been arrested so far and remain in remand custody until April 17. Among those detained are an assistant manager from the bank’s payment and settlement division and his brother, who allegedly exploited access to NDB’s data systems.

NDB reiterated that no customer account balances have been affected and that all banking services continue without interruption. The Central Bank of Sri Lanka also confirmed that NDB’s capital adequacy and liquidity ratios remain above minimum regulatory requirements, echoing earlier depositor assurances.

The fraud, first disclosed in early April, has already triggered a Fitch downgrade, a parliamentary committee investigation, and IMF scrutiny. The Interpol request marks the first time an international law enforcement agency has been formally brought into the case.