Something More Than Night - Ian Tregillis

Something More Than Night is a Dashiell Hammett and Raymond Chandler-inspired murder mystery set in Thomas Aquinas's vision of Heaven. It's a noir detective story starring fallen angels, the heavenly choir, nightclub stigmatics, a priest with a dirty secret, a femme fatale, and the Voice of God.

Somebody has murdered the angel Gabriel. Worse, the Jericho Trumpet has gone missing, putting Heaven on the brink of a truly cosmic crisis. But the twisty plot that unfolds from the murder investigation leads to something much bigger: a con job one billion years in the making.

Because this is no mere murder. A small band of angels has decided to break out of Heaven. They need a human patsy to make their plan work.
Much of the story is told from the point of view of Bayliss, a cynical fallen angel who has modeled himself on Philip Marlowe. The yarn he spins follows the progression of a Marlowe novel the mysterious dame who needs his help, getting grilled by the bulls, finding a stiff, getting slipped a mickey.
Angels and gunsels, dames with eyes like fire, and a grand maguffin, Ian Tregillis's Something More Than Night is a murder mystery for the cosmos.