The horror potential of a Jack-the-Ripper mentality masquerading behind the trustworthy facade of a clergyman, a policeman or that of any man whose occupation confers respectability, is fully exploited here. It is murder with mayhem as three sisters, ""professionals"", are slain in a series. The plot shifts around with scenario smoothness and the dialogue rings true as one theory after the other -- Reviate? old ""client""? law officer? -- is played out to an ending that suggests another book to come.