Prosecutors are investigating former Raiffeisen Chief Executive Pierin Vincenz, and the bank has also lodged a complaint against the former long-standing banker. But the ball got rolling elsewhere entirely.

Aduno Group said in a surprise statement on Wednesday that it had lodged a criminal complaint against Pierin Vincenz, a well-known Swiss banker. The Zurich-based firm said it notified authorities on December 21 that it suspected two people – its former Chairman, Vincenz and another, unnamed person – of acting in bad faith.

The admission comes shortly after Raiffeisen, a cooperative lender, said Vincenz was being criminally investigated, and that the bank has also lodged a criminal complaint in an effort to gain «conclusive clarification» about possible wrong-doing.

Vincenz stepped down as Chairman of Aduno in June. The cashless payments specialist didn't name the second person it identified to prosecutors.

Explosive Findings

Once a powerful Swiss banker, Vincenz has successively retreated from positions of power in Swiss finance as the probe widened. A spokeswoman for Zurich's prosecutor confirmed that it opened a criminal investigation after being notified by Aduno.

The Swiss firm hadn't disclosed its role or the criminal probe until now in order to protect the investigation, it said. Its board had mandated an independent investigation through Baumgartner Maechler, a Zurich securities law firm, with looking at various Aduno takeovers in recent years. The results were explosive enough to spark the criminal investigation, shortly before Christmas.

Vincenz is inextricably linked with Aduno: he had been Chairman of the firm since its founding in 1999 until last year.