A pensioner collapsed and died in Bow after brawling with a fellow bus passenger.
Police have launched a murder investigation after the victim came to blows with another man aboard a route 488 bus.
Both got off in Parnell Road and carried on fighting in the street, according to police.
The victim, believed to be in his late 60s, then collapsed and was taken to an east London hospital where he later died.
Police were called to the scene at 8.45pm on Monday, April 3 to reports of two men fighting.
They arrested a 73-year-old man near the scene on suspicion of grievous bodily harm and remains in custody at an east London police station.
Detectives from the Homicide and Major Crime Command are investigating and have appealed for anyone who witnessed the fight on the road or bus to come forward.
Formal identification and a post-mortem examination will take place in due course.
Anyone with any information is asked to contact police on 0208 345 3985 or via Twitter @MetCC
Or contact Crimestoppers anonymously on 0800 555 111.
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