An elite runner from Sierra Leone who disappeared after finishing the women's race in 20th place is still missing.
Police said earlier that she had been found in Greenwich, but later re-issued an appeal.
Mami Konneh Lahun, 24, disappeared after competing in the 26.2 mile race on Sunday alongside an estimated 36,000 people.
Scotland Yard launched an investigation after she did not return to her temporary accommodation in Greenwich where she had been staying since arriving in the UK on 7 April.
Concerns had been growing for Ms Konneh Lahun, who police said had no known links to the UK and did not have a mobile phone. She was also due to fly home on Monday.
The elite athlete, who won the Sierra Leone and Liberia marathons last year, completed the 34th London Marathon in two hours 46 minutes.
Competitors had to contend with bright sunshine and temperatures that had reached 16C (60.8F) by the time they crossed the finish line in St James’s Park.
The men’s race was won by Kenyan world record holder Wilson Kipsang, who finished in a course record time of 2 hours 4 minutes and 29 seconds.
The women's title was taken by Ethiopian Edna Kiplagat in a time of 2 hours 20 minutes and 21 seconds.
A 42-year-old man, who has not been named, died during the event. He could not be saved by medical teams after collapsing immediately after finishing the race.
Hugh Brasher, race director of the Virgin Money London Marathon, said: "We did very unfortunately have one death of a runner, who had finished and our thoughts are very much with the friends and family of that runner. Overall it was a fantastic day, but it always is tinged with a little bit of sadness when something like that happens."
Additional reporting by Press Association