A stimulating glacial character drama / mystery

Those Who Disappeared is a stimulating and thought-provoking character drama, following the quest of a famous and successful modern artist to solve the mystery surrounding his father's death.
Charles Treherne, then a 25-year-old postgraduate student, disappeared high on the (fictional) Handeck Glacier in Switzerland, while hiking alone. Thirty-two years later, his remains emerge from the glacier (a not uncommon occurrence in real life). Berlin-based artist Foster Treherne is his sole surviving next-of-kin, a curious situation, since he was in utero at the time of Charles' disappearance.
Somewhat thrown by the discovery, Foster is accompanied to Bern by an American diplomatic aide, Daniela Herrera, to attend a forensic facility and accept his father's few personal effects. It's here that he's made aware that not all is straightforward as it seems - Charles' body bears signs of a fight, inconsistent with postmortem injuries caused by the movement of the glacier. As the forensic director speculates, "...if someone had been on the mountain [with him], they might have had some questions to answer.".
Among his father's personal effects is his journal, covering the time of his postgraduate days in Bologna, mentioning various friends (Foster's English mother included) and associates from the mysterious Piranesi Society and a few personal animosities. With the assistance of Daniela and his P.I.-on-retainer, Sigrid, Foster begins to track down the members of his parents' circle and determine who really was on the mountain the day Charles disappeared. Given that his mother committed suicide when Foster was only a year old, he receives some level of sympathy from the now fifty-something group of potential suspects, but he feels he's being stonewalled.
Foster's investigations take him to various points around western Europe, across the Atlantic to New York and Connecticut, and ultimately to a final showdown which coincides with his attendance at the famed Venice bienniale art festival.
I found this an engaging and intriguing story about a young man who has grown up with plenty of talent, money and a privileged education, but largely without family roots (neither set of grandparents were particularly interested in his upbringing). Not unsurprisingly, his search for the truth about his father's (and mother's) deaths becomes, to some extent, a voyage of discovery into himself. There were several surprising twists and turns, culminating in a satisfying resolution that felt realistic, in spite of the dramatic circumstances.
My thanks to the author, Kevin Wignall, publisher Amazon Publishing UK / Thomas Mercer and Netgalley for the opportunity to read and review this title.