Thomas "Tom" Hepburn was the oldest sibling of actress Katharine Hepburn. On April 3, 1921, while visiting friends in Greenwich Village, Hepburn found her older brother Tom (born November 8, 1905), whom she idolized, dead from an apparent suicide. Although many reports have said Tom had hanged himself, according to the coroner's report detailed in William J. Mann's biography, Kate The Woman Who Was Hepburn, Tom had tied one end of a sheet around his neck, the other to a post, and had effectively strangled himself. The Hepburn family denied it was suicide and insisted Tom's death must have been an experiment gone awry. Katharine Hepburn was devastated and sank into a depression. She shied away from other children and was mostly home-schooled. For many years she used Tom's birthday (November 8) as her own. It was not until her 1991 autobiography, Me: Stories of My Life, that Hepburn revealed her true birth date of May 12, 1907.

Source: Wikipedia