Out of Sight 2: Invisible People

Nocturnal excursions enable Rakvir Stagarnik to gain useful information about who killed the Kerkrander and how the two Thanians were involved. Tracking some of these people leads to an empty house in a wealthy quarter of Ralchis and the realisation that a huge conspiracy is taking place. Through the intervention of a corrupt merchant and an old friend, Rakvir and Arhilka are able to put pressure on a high-placed merchant adventurer, while continuing the pretence of negotiating the sale of their "ghan". But before he confesses, he is captured and murdered by people who remain largely invisible.
"Out of sight - 2 Invisible people" is the second of three volumes where Rakvir and Arhilka Stagarnik investigate murder and corruption in the City of Ralchis. It is part of the series which include "Through Fire" and "By Water", set in a distant planet, not too dissimilar from our own, written by Richard Hernaman Allen, a former Commissioner of Customs & Excise.