The victim, believed to be in her 20s, was pronounced dead at the scene on Thursday after being struck by building debris, believed to be a concrete window frame, in Hanover Square, in central London.
A Scotland Yard spokeswoman said yesterday that police were working alongside the Health and Safety Executive (HSE) to try to establish what happened.
The emergency call was made by a man delivering electrical cables to the area. He said that the woman was “flattened”, and that he thought he saw her “draw her last breath”.
He said he approached the woman after the 999 operator told him to get closer. “Her eyes were open and I saw her hand move and then I think I saw her last breath and then the light went out: she’d gone,” he said.