The attack, in which one man died and another was shot in the face, followed a high-speed chase which is believed to have been prompted by a minor accident in which two cars bumped into each other in north London.
The murder comes shortly after the stabbing to death of Stephen Cameron, 21, during an argument with a motorist on a sliproad of the M25 junction at Swanley, Kent, on 19 May. There is increasing concern about road rage, in which frustrated motorists go berserk and strike out.
In the latest incident the killer is believed to have waved a gun from the window of his car as he chased three men in their vehicle for about a mile.
At first the police believed the incident, which happened at about 11pm on Monday, was most likely a drugs shooting, but after interviewing witnesses they now think it was road rage.
The case began after a minor collision at a junction of Seven Sisters Road and Woodberry Grove, Manor House, between a red Mitsubishi car and a "sports type" car. The Mitsub-ishi suffered slight damage. Witnesses said that the three men in the Mitsubishi failed to stop.
The second car gave chase and the driver began waving what was described as a "stick" out of the window - police believe this was probably a gun.
The Mitsubishi driver fled at high speed and, believing that the pursuer had been shaken off, parked in nearby Surrey Gardens. But the three men, all of whom were born in Ghana, were then confronted by a white man who entered the street on foot after parking around the corner. An argument began, and the man produced a handgun from his pocket or waistband and shot one of the car's two passengers - a 41-year-old man - in the chin.
He then shot a second passenger twice in the head. The 35-year-old victim, a Ghanaian holidaymaker, died instantly.
The Mitsubishi driver was also threatened by the gunman, but he ran away and managed to escape. The injured passenger was treated in hospital and released the following day.
The gunman is described as white, in his mid-thirties, about 5ft 8ins tall and well-built. He spoke with a London accent.
Sandy Myles, 47, was in his home nearby at the time of the shooting. He said: "I looked out and saw a group of men shouting and yelling. It was one huge row. After looking out the front door I dialled 999. The argument then shifted to the other end of the road and I could see there were 10, maybe more, people involved.
"As I opened the front door I heard one gunshot. I slammed the door shut, then rang the police again and as I was doing so there were another two shots."
Police are appealing for witnesses.Reuse content