Emissaries From the DeadPaperback - 2008
Two murders have occurred on One One One, an artificial ecosystem created by the universe's dominant AIs to house several engineered species, including a violent, sentient race of sloth-like creatures. Under order from the Diplomatic Corps, Counselor Andrea Cort has come to this cylinder world where an indentured human community hangs suspended high above a poisoned, acid atmosphere. Her assignment is to choose a suitable homicide suspect from among those who have sold their futures to escape existences even worse than this one. And no matter where the trail leads her she must do nothing to implicate the hosts, who hold the power to obliterate humankind in an instant.
But Andrea Cort is not about to hold back in her hunt for a killer. For she has nothing to lose and harbors no love for her masters or fellow indentures. And she herself has felt the terrible exhilaration of taking life . . . .