Of love and evil [the songs of the seraphim, a novel]

"Former government assassin Toby O'Dare is summoned to fifteenth-century Rome at the height of the Italian Renaissance to solve a poisoning murder linked to an earthbound spirit, a case complicated by dark ecclesiastical plots."@en
"In fifteenth century Rome, Toby O'Dare, a recently retired government assassin, receives a visit from the angel Malchiah. The heavenly figure instructs O'Dare to solve a grisly murder. But during the investigation, O'Dare discovers that the city is being haunted by an ancient demon and that solving the murder may have disastrous consequences for all of Rome."
"In fifteenth century Rome, Toby O'Dare, a recently retired government assassin, receives a visit from the angel Malchiah. The heavenly figure instructs O'Dare to solve a grisly murder. But during the investigation, O'Dare discovers that the city is being haunted by an ancient demon and that solving the murder may have disastrous consequences for all of Rome."@en
"Toby O'Dare, former government assassin, is summoned by the angel Malchiah to fifteenth-century Rome--the city of Michelangelo and Raphael, of Leo X and the Holy Inquisition--to solve a terrible crime of poisoning and to uncover the secrets of an earthbound restless spirit, a diabolical dybbuk."