A member of the public found a man with serious head injuries in broad daylight in a residential London street.
The 24-year-old was discovered lying face-down in High Cross Road, Tottenham on Saturday afternoon.
A relative phoned the injured man, but was told by a member of the public who picked up his phone that he was lying unconscious.
The relative then rushed to the scene and collected the injured man, driving him to his house before calling an ambulance.
Police and paramedics were sent to the property around 4.10pm on Saturday, and arrived to find the victim suffering head injuries.
He was taken to hospital, where his condition was on Wednesday described as “life-threatening”.
Scotland Yard says a number of witnesses were at the scene in High Cross Road, but had left by the time officers arrived, and police have not been able to trace them.
The injured man is thought to be of Turkish descent, medium build, with a bald head, and a black moustache and beard.
He was wearing a white vest, black jacket, jogging bottoms and trainers when the incident happened.
Detective Inspector Oliver Franks from North Area CID said: “Unfortunately, due to the circumstances, we have not been able to trace witnesses to this incident and we urgently need to understand what has happened. It is important to remember that we are keeping an open mind about how the man was injured.
“We know there were people at the scene and we are appealing for those people to come forward and tell us what they saw.
“We believe the critical times are between 12.45pm to 2pm and we would like to speak to anyone who was in the area and thinks they may have seen this man, or were driving through and may have dash cam footage.
“This man is critically ill and we urgently need the public to come forward and tell us what they saw.”
