River of Souls. Larh Thomas Mysteries, #2

Embarrassing footage emerges from a shipwreck in Mounts Bay, dating back to the nineteenth century. The footage shows the skeleton of Captain Andrew Hamilton alongside two black women, a mother and daughter. The skeletons were chained up in the hold of the ship when it sank. The footage is doubly embarrassing because one relative of the captain is the Foreign Secretary, and his son is an MP. The captain was an acquaintance of Queen Victoria's wayward older son, Bertie.
Navy divers are ordered to remove the evidence soon after it is discovered. A tin of Captain Hamilton's possessions is held by an American university, which includes a map of the river Congo where Captain Hamiltion had been stationed, when he worked for the Belgians while exiled from the Navy in disgrace. Larh Thomas organises an expedition to the mission station, to try and recover the evidence which is held here.
The professor has leant her two black students, a Nigerian man, and an American woman, eager to visit her roots. They are accompanied by a TV camera crew lead by a well known news reporter who has been suspended because of her links to the Hamiltons. The expedition, funded by crowdfunding when the authorities get cold feet, hires an old boat and proceeds up river, but local gangsters become involved when diamonds are found at the mission.
Africa's complicated past, and its links to the elite in England, combine with the DRC's complicated present, to create a powerful backdrop to the expedition.  The team then have to extricate themselves safely from the political chaos they cause.