The key suspect in a parcel bomb attack that wounded a Ukrainian multi-millionaire and two others on Monday in Monaco is a Ukrainian woman who disguised herself as a man, local authorities say.

Monaco's Prosecutor General, Stéphane Thibault, confirmed the suspect was a Ukrainian woman in her 30s, currently registered as living in Germany.

The suspect, who was captured on CCTV wearing a black fisherman's hat, is believed to be a woman who tried to pass off as a man, according to local news