Fashanu, 36, apparently fled to Britain while Maryland police were searching for him in connection with the alleged assault after a beer party at his apartment on March 25.
He was charged April 3 with second-degree sexual assault, first-degree assault, and second-degree assault. Under Maryland law, the sex offense carries a maximum 20-year jail term.
Scotland Yard said a member of the public called police at noon Saturday reporting that a body had been found in a garage complex underneath a railway bridge in east London.
A medical examiner, who went to the scene with police, confirmed Fashanu's death. Police said the exact cause of death had not yet been established.
Police sources, speaking on condition of anonymity, said it appeared Fashanu committed suicide by hanging.
Fashanu was set to coach a new minor-league professional soccer team, the Maryland Mania, in the town of Columbia and was living in Ellicott City. On March 25, he allegedly invited six youngstersall below Maryland's legal drinking age of 21to a beer party at the apartment.
According to court documents, the 17-year-old awoke after the party to find Fashanu performing a sexual act on him. A subsequent medical examination revealed evidence of a sexual assault, documents said.
Fashanu European soccer star who earned as much as $1.67 million early in his career. But he rapidly found himself out of the limelight. A knee injury kept him out of the game for six years in the 1980s. Attempts to salvage his career were failures. He blamed the failures on prejudice after admitting publicly that he was gay in 1990.
Spectacular details of his sex life, including fabricated claims of affairs with senior Conservative Party lawmakers, were splashed across the tabloid newspapers as he came out in a series of interviews in 1990. And his flamboyant lifestyle kept him in the headlines.
Fashanu said all he wanted was acceptance.
"If people feel comfortable with me as a person, then my sexuality is not important," he said recently.