The man shot dead metres form his home on Christmas Eve has been named by the Met Police as Swedish national Flamur Beqiri.
The 36-year-old was fatally shot near his home in Battersea, south-west London.
Police were called to reports of shots being fired in Battersea Church Road at about 9pm and found a man with gunshot wounds.
He was pronounced dead at the scene, Scotland Yard said.
Detective chief inspector Jamie Stevenson, of the Specialist Crime Command, is leading the investigation. He said: “Our investigation is in the very early stages and we are still working to establish what the motive could be that has led to a man losing his life in such a horrific way, on Christmas Eve, in front of his family.
“They have been devastated by this horrible event and are being supported by specialist officers.
“We know that the victim was returning home with his wife and young child following an evening out, when he was shot just yards from his home. The assailant then fled on foot in the direction of Battersea Bridge Road.
“The attack took place at 21:00hrs in the evening. Not only would many people have been out going about their business, but I am sure many residents would have been alarmed by the sound of the disturbance and gone to see what had happened.”
Police have asked anyone who was in the area, who may have seen someone fleeing the area or loitering close to the scene of the crime, to contact police immediately on 101, quoting CAD 6410/24Dec.