Brigadier-General Edgar William Cox, DSO, FRGS (9 May 1882 - 26 August 1918) was a senior intelligence officer on the British General Staff throughout most of the First World War who drowned in suspicious circumstances whilst swimming in August 1918 shortly after the German successes in the Spring Offensive which drove the Allied armies back a large distance. Although officially an accident, suspicions of suicide surrounded his death, which occurred just days before the beginning of the Allied counterattack which would eventually defeat the German army.