The bank had concluded in October that an earlier spy scandal was an isolated incident

The spying scandal engulfing Credit Suisse has worsened after the bank admitted that a second senior employee had been followed by private detectives.

The revelation is an embarrassment for the Zurich-based lender, which in October had concluded that a separate spying incident was an isolated affair.

A review by the bank and Homburger, a Swiss law firm, has found that in February Peter Goerke, who was then the bank’s head of human resources, was tailed “for a period of several days”.

Homburger has not found evidence that Tidjane Thiam, Credit Suisse’s chief executive, or other top directors had any knowledge of either espionage operation. Nevertheless, the uncovering of another spying controversy is a blow to the reputation of Credit Suisse, which is Switzerland’s second-largest