The Adventure of Colonel Niven's Memoirs

A WW II spy, Colonel Alec Nivin, is on a book tour in New York concerning his memoirs in which he accuses a variety of people of war crimes and treasonous acts. Ellery's galpal, Jenny O'Brien, finds the erstwhile spy dead in his hotel room having been stabbed with an antique dagger. Everybody except Jenny is a suspect in this one.