An 18-year-old who claimed he was the victim of an attack linked to the murder of Marsha McDonnell has been arrested for wasting police time.
An attack on a 17-year-old girl has been linked to Marsha's murder
Miss McDonnell, 19, a gap-year student, was killed near her home in Hampton, south west London, in the early hours of 4 February after a night out with friends.
She had been hit on the head with a blunt instrument.
The man was arrested by Scotland Yard's Specialist Crime Directorate and bailed to return on Wednesday.
Officers investigating Miss McDonnell's death had been considering two attacks which were alleged to have taken place within a three-mile radius of where she was killed.
A 17-year-old girl was left with head injuries after being attacked in Walpole Gardens, Strawberry Hill, on 8 January at about 2100 GMT.
She has no memory of being attacked and it was originally assumed she slipped on ice.
The 18-year-old man said he managed to escape unhurt after a hooded attacker had lunged at him with a blunt instrument in Hampton Hill a few weeks after Miss McDonnell's murder.
A Scotland Yard spokesman said the third incident was no longer being linked to the murder investigation and the teenager had been arrested for wasting police time.
He said: "The allegation caused a lot of panic in the community and we held a press conference to reassure the community.
"A lot of police action was taken in the area including checking CCTV, interviewing him and making sure he was okay and carrying out door-to-door inquiries.
"Serious assault investigations take a lot of time and effort."