His body was found by a member of the public in a lock-up garage, used as a car park, in Shoreditch on Saturday afternoon.
A post-mortem examination proved inconclusive but further tests are being carried out. A spokesman for Scotland Yard said they were not treating the death as suspicious. Eyewitnesses said he had been seen drinking in one of the nearby gay bars on Friday afternoon. He had seemed "chirpy".
The unnamed teenager allegedly assaulted by Fashanu in the US was one of six - all below the drinking age for Maryland of 21 - who spent the evening drinking beer at Fashanu's house. He claimed he went to bed around midnight and woke in Fashanu's bed eight hours later to find he was being sexually assaulted by the football star.
Fashanu, 37, a born-again Christian, was questioned and charged following the alleged incident on 25 March. A warrant for his arrest was issued by police in Howard County, Maryland, a week later when they arrived at his flat and found it empty and his clothes gone. According to court documents, a medical examination found evidence of sexual assault.
Fashanu, who denied the allegations, was charged with second-degree sexual assault - an offence which carries a maximum 20-year jail term and first- and second-degree assault.
Eric Hall, a football agent who arranged for Fashanu to sell the story of his homosexuality to a newspaper in 1990, said yesterday that he felt "so guilty" after illness prevented him from returning a telephone call from Fashanu last week. "I had kept in touch with him, and little did I know last week he phoned me from America. I hadn't heard from him for quite a few months." Fashanu, the first prominent British sportsman to be openly gay, had a notoriously difficult relationship with his younger brother John, the former Wimbledon and England striker.
On Friday, John said he had not spoken to his brother for seven years, but yesterday his lawyer, Henri Brandman, said he was "shocked and distressed. Although there were periods of disagreement between them, there were also many occasions when they have enjoyed special times together", he said.
Justin Fashanu was acknowledged as the better player of the two brothers but the macho world of football did not take kindly to his revelation of homosexuality eight years ago.
He was speedily dropped by Nottingham Forest, in the First Division (now the Premiership), and found himself playing for Torquay United in the Third Division. He was bitter about his fate and blamed what he saw as a deep-seated prejudice in the English game. "You have to understand that footballers are very narrow-minded people. When you put yourself in the firing line, you are open to attack," he said.
He did not help himself when lurid details of his sex life, including fabricated claims of affairs with senior Tory MPs, were splashed across the tabloid newspapers when he came out in a series of interviews in 1990.
He was sacked from his last British team, Edinburgh-based Hearts, and moved to Ellicot City to coach Maryland Mania Club, a new professional team set to start playing the second-division A-league next year.
It was a long way down for the striker who was the first black player to be transferred for a pounds 1m fee.
In a final humiliation he lost touch with his brother - the result of an alleged attempt by John to dissuade him from revealing his homosexuality with a large cash payment.
What little stability there was in his life came from the couple who fostered John and Justin, aged five and six. They were taken in by Alf and Betty Jackson after their parent's marriage broke up. But despite their respectable upbringing, his brother has had his fair share of controversy. Last year he was acquitted of conspiracy to fix Premier League matches after a 45-day trial.
John, former co-presenter of Gladiators, was accused of being the middle- man between a gambling syndicate in Indonesia and two English-based goalkeepers, his team-mate Hans Segers and Bruce Grobbelaar, once of Liverpool. Since the trial he has kept out of the public eye and devoted himself to his business activities.
Justin had also kept a low profile until last week when, it can only be assumed, the shame of the charges against him caused him to take his own life.
Obituary, page 16