A non-governmental organization is lodging a criminal complaint against Credit Suisse over million-dollar tuna bonds in Mozambique. The Swiss bank denies knowing of any wrong-doing in the scandal.

The Swiss bank's link to a corruption scandal in Mozambique just got more unpleasant: Swiss non-governmental organization Public Eye is filing a criminal complaint against Credit Suisse with Switzerland's attorney general, it said in a statement on Monday. The move follows a lawsuit filed by the south African nation against the Zurich-based bank last month.

The Swiss complaint is awkward for Credit Suisse, which has sought to downplay its ties to the oil- and gas-rich eastern African nation. The country defaulted last year, after it surfaced that some funds intended for infrastructure like tuna-fishing boats allegedly went towards military equipment instead. Credit Suisse and VTB had emitted bonds with a coupon of 8.5 percent for parts of the loans granted to Mozambique, but not told investors it granted further loans to the impoverished country.

Public Eye said it wants Switzerland's attorney general to clarify whether Credit Suisse adequately supervised its subsidiary, which issued the bonds, and fulfilled its duties to combat illegal activity. Credit Suisse Chairman Urs Rohner said the Swiss bank didn't know of any wrong-doing by former employees, when he was asked about the scandal at the Swiss bank's shareholder meeting on Friday.