Clouds of Witness

First published in 1926, 'Clouds of Witness' is a mystery novel by Dorothy L. Sayers, an English crime writer, poet, and student of classical and modern languages, best known for her mysteries, a series of novels and short stories set between the First and Second World Wars.
As Lord Peter Wimsey appreciates his time in Corsica, he's brought back to actuality when all of the headlines declare that his brother, Gerald, has been charged with murder. Gerald, who had been on a hunting expedition at the family's estate in Yorkshire with his brother-in-law, had gotten into a fight with the man about his disgraceful past. Hours later, the man is dead, and Gerald is the primary suspect. As Gerald claims his integrity, it's up to Wimsey to figure out who the real killer is and save his brother.
"But to Lord Peter, the world presented itself as an entertaining labyrinth of side issues."
-Dorothy L. Sayers, Clouds of Witness