No Shred of Evidence

Author Charles Todd is actually a mother and son writing team and this is the latest (2016) installment in the "Inspector Ian Rutledge" series, which boasts over 2 dozen books. The time frame is just two years after the end of WWI in England, and protagonist Ian Rutledge is one of the many soldiers who has come home in worse shape than he left it. He was buried alive in a suicidal mission at the end of the war and carries the ghost and guilt of one of his former soldiers with him as a constant commentator and frequent tormentor.
In the north of Cornwall, 4 young women from moneyed families take advantage of a last sunny day and go out for a row on the Camel River only to see in the distance a young man from town, Harry the banker's son, apparently in dire straits on a sinking dinghy. They race to reach him before he drowns but are unable to haul him aboard. When they try to extend an oar to him, they lose control, hit him on the head, and are on the brink of capsizing. A farmer on shore swims out and helps pull the unconscious man aboard; however, when the group reaches shore, he swears to one and all that he saw the women trying to drown the man. The women are taken into custody but then released to the home of the local magistrate, Grenville, who is the father of one of the young women. Grenville also calls in a favor from the Home Office, and Scotland Yard sends an investigator, who dies of a heart attack two days into the inquiry. So now Rutledge is sent and it turns out he knows one of the accused. It is their word against that of the adamant farmer and, when Harry remains comatose and dies of his injuries, Rutledge is the only one who can save the women from the gallows--if he can find any evidence to support their version of events.
When a series of seemingly unrelated brutal beatings and murders occur in the same cluster of villages,  Rutledge is the only one who can seem to connect the dots. This was really a very clever plot, and I would definitely read other books in the series and also to check out the other series by this team, the "Bess Crawford" books.