Three shootings, including two murders, have been officially linked by police.
On Thursday morning Nezir Golaj, 45, died after being shot several times on Hendon Way in north London, near his home in Garth Road, Cricklewood.
On Friday a man, 43, was injured in a shooting in Wightman Road, Hornsey.
The same night Osman Grbic's body was found in Upton Park, east London.
Police have been given extra time to question a man, 50, over the shootings.
The man was arrested in Bounds Green in Friern Barnet on Friday evening before officers found 58-year-old Mr Grbic's body at his flat in Milton Avenue.
Mr Golaj was shot as he got into his car in Garth Road. The car travelled across Hendon Way and came to a stop on the six-lane A41 during the morning rush hour.
In the second murder a friend of Mr Grbic alerted police about his disappearance after which police forced their way into the flat and found the body.