The benson murder case

"The Benson Case" is the first novel in a series of books about private detective Philo Vance. Vance, a stylish gentleman from New York with an extraordinary intellect, helps the police solve complicated cases. A well-known stockbroker in the city, Alvin Benson, a cynical and cruel man, is killed in his country estate. There were many complex intrigues around the victim, so there are also many suspects - who is the killer?