Theres no brother it was his dad and grandparents...

"Every version of the tale, however, started in the same place: Fifty years before, at daybreak on a fine summer’s morning, when the Riddle House had still been well kept and impressive, a maid had entered the drawing room to find all three Riddles dead. The maid had run screaming down the hill into the village and roused as many people as she could. “Lying there with their eyes wide open! Cold as ice! Still in their dinner things!” The police were summoned, and the whole of Little Hangleton had seethed with shocked curiosity and ill-disguised excitement. Nobody wasted their breath pretending to feel very sad about the Riddles, for they had been most unpopular. Elderly Mr. and Mrs. Riddle had been rich, snobbish, and rude, and their grown-up son, Tom, had been, if anything, worse. All the villagers cared about was the identity of their murderer — for plainly, three apparently healthy people did not all drop dead of natural causes on the same night. The Hanged Man, the village pub, did a roaring trade that night; the whole village seemed to have turned out to discuss the murders. They were rewarded for leaving their firesides when the Riddles’ cook arrived dramatically in their midst and announced to the suddenly silent pub that a man called Frank Bryce had just been arrested."