It was originally thought that he had jumped from his own office on one of the lower floors, where a window was found open. But the new investigation has uncovered evidence inconsistent with that belief.

Marks on his body suggested a fall from a greater height, while there were also signs that he might have been grasped by another person. The way in which he fell, captured by a surveillance camera, is also  thought to be unusual in cases of suicide. 

There were traces of white paint and varnish on the soles of his shoes and, while those materials were being used in renovation work on the upper floors of the building, the work was not being carried out at that time on the floor from which Mr Rossi was said to have thrown himself.

His family has also pointed to inconsistencies involving his watch, which they say was found some distance from his body and may even have fallen to the ground 20 minutes afterwards, and to a call to his phone that seemed to have been answered after the alleged time of his death.

The police have carried out a reconstruction of the fall in an attempt to untangle the mystery.

There are suggestions that bank executives and influential members of Italian society engaged in a conspiracy of silence over the bank’s hidden losses and its attempts to cover them up: MPS executives, magistrates, journalists, a priest and even a former government minister are alleged to have agreed to say nothing about the affair at gatherings that resembled masonic meetings.

One former MPS executive, Pierluigi Piccini, spoke in a television broadcast in 2018 of alleged erotic parties in a seaside villa in which magistrates involved in the investigation into Mr Rossi’s death were said to have taken part. Prosecutors opened an investigation into abuse of office and aiding and abetting prostitution but it was later closed.

Two days before his death, Mr Rossi sent an email to a senior executive at the bank warning him that he would tell magistrates everything he knew about the bank’s hidden losses and the cover-up.

MPS declined to comment while the police investigation was taking place.