This book is number 2 in the De Gier and Grijpstra police procedurals. It was published in 1976. The country in question is the Netherlands. The crime in question this time was the stabbing of Maria van Buren on her houseboat. The investigation revealed that she was a mistress to three well-placed men of wealth. How does one investigate an American military officer assigned to the Hague, the diplomat from Belgium, and one of the wealthiest men in Holland? Very carefully.
Van Buren was discovered to have come from the island of Curacao, so the commissaris, as bosses tend to do, said he would fly to the Caribbean island to find out what he could about her. The two plucky detectives also went to an island–off the coast of Netherlands; cold and wet.
As it happens, van de Wetering spent 7 years of national service as a reserve cop. While he did not do any detecting, it did give him an inside look at the police of his home country. In fairness, the world was his home. He spent most of his early life in South Africa, England, Australia, Japan, Colombia, and many stops along the way before moving to Surry, Maine, USA, where he spent his last few decades, dying there in 2008.
His writing has spunk.