Credit Suisse Group AG said an investigation concludes that former executive board member Peter Goerke was "placed under observation" by a third-party firm mandated by former COO Pierre-Olivier Bouée for several days in February.

Bouée, who was found to have issued another mandate earlier to observe the Zurich-based bank's former wealth management head Iqbal Khan, resigned from his post Oct. 1 after taking full responsibility over the Khan scandal.

The latest probe, conducted by the bank's board of directors and law firm Homburger AG, did not find CEO Tidjane Thiam, or any other executives and directors, being aware of the observation of Goerke until it was reported by the media, according to a Dec. 23 release.

Credit Suisse said the employees questioned during the Khan spying investigation did not respond truthfully about any other observations and did not disclose the incident regarding Goerke. The bank noted that it has terminated the employment agreement with Bouée.

The bank said it has issued an apology to Goerke.

Earlier in December, Swiss publication Neue Zürcher Zeitung reported, citing documents, that Goerke, who was Credit Suisse's former head of human resources, was followed by private investigators in February.

Credit Suisse's statement comes after the Swiss Financial Market Supervisory Authority, or FINMA, disclosed that it has appointed an independent auditor to investigate the lender's observation activities and corporate governance. The regulator added it will disclose further information following the conclusion of the probe, which is expected to take several months.

Credit Suisse said it will continue to cooperate with FINMA and the independent auditor.

The group is also facing spying allegations from Colleen Graham, a former executive at a joint venture owned by Credit Suisse, who claimed that she was followed by a woman over the course of three days in July 2017 in retaliation over an accounting dispute at the firm, according to The Wall Street Journal.