Behind a typically abstruse giallo title (the plot's link to a butterfly of any kind is extremely tenuous) lies a film that rarely feels like a typical giallo, with more police procedure and courtroom drama than usual. Director Duccio Tessari's film opens in familiar territory with the murder of a young woman in a park, the killer, in raincoat and hat, making his escape, but witnessed by several people. The police investigate the crime scene, forensics gathering numerous pieces of evidence, all of which points to TV reporter Alessandro Marchi (Giancarlo Sbragia) as the guilty party. The rest of the first half of the film is dedicated to the trial of Allesandro, with dreary flashbacks and cross-examination making the film something of a chore to sit through.
Found guilty of murder, Allesandro is sentenced to life, but while he is in prison, the killings continue, the modus operandi the same as before, the culprit contacting the police with a whispered phone call. When Allesandro's mistress comes forward with vital information that seems to prove his innocence, Allesandro is freed (much to the annoyance of his wife, who also has a lover). After much intrigue, Tessari eventually pulls together all the plot threads for an unexpected twist ending that goes some way to make the duller moments seem a bit more worthwhile. As far as the death scenes go, they are extremely tame and likely to disappoint fans of Argento or Fulci, and despite a fair few attractive women, the level of nudity is also fairly low.
Perhaps the most notable things about the film are its police inspector's strange obsession with coffee, and the cop who falls over running down some stairs during a chase on foot through the streets of Milan (it looks unintentional and is never spoken of).
5.5/10, rounded up to 6 for IMDb.
