Uber has used it's smartphone software to pinpoint which of it's 45,000 London drivers were in the vicinity when Sarah Everard vanished.
The taxi giant has asked them to contact the police if they have any relevant information in relation to Sarah's disappearance, a spokesperson said.
She was last seen walking home alone on the South Circular Road and detectives fear she may have been abducted.
Police last night erected a 100 metre cordon along the road, indicating it could hold vital clues to Sarah's disappearance.
Earlier officers with sniffer dogs were seen searching outside the nearby Oaklands Estate and gardens in surrounding streets.
Others were lifting drain covers and searching bins along the road.
Officers have specifically appealed for motorists on that section of her route, which is not covered by CCTV, to send them dash-cam footage.
Uber said it has used the tracking software from its app in an effort to help find Sarah, 33, who was last seen in south London at around 9.30 last Wednesday.
The marketing executive, who was wearing headphones, was last seen on a doorbell camera walking alone on the Poynders Road section of the South Circular, from the junction with Cavendish Road, in the direction of Tulse Hill.
It is around the halfway point between the friend's home she left on Clapham Common and her Brixton flat.
She was not picked up on a number of cameras further along her most likely route home.
The Durham University graduate had spent around 15 minutes on her phone to her boyfriend Josh Lowth before her mobile reportedly either switched off or went dead.
Josh, 33, whose LinkedIn says he is Marketing Director at MA Exhibitions, reportedly raised the alarm to police when she failed to meet him as they had arranged the next day, her aunt said.
Speaking at Josh's family home in Sidcup Kent, his father Chris said: We are concerned, like everybody is. We really, really want to see her back.'
“The whole family is obviously very worried about her and just wants her home safely.
“We're all pulling together and praying that this awful situation is quickly resolved. We want to thank the media for all their help.”
Josh, from Brixton, shared a post on Facebook, which said: “Sarah is still missing. Please share this post to help us to find her. Today, more than ever, we miss our strong, beautiful friend.”
Sarah’s uncle Nick said on Tuesday: “The family are absolutely distraught today and it’s getting worse as the days go on, we still have no more information.
“I don’t know London well but I fear there could have been some bad people about who approached her. The family are searching with Sarah’s friends who have been absolutely amazing.”
Det Chief Insp Katherine Goodwin, who is spearheading the probe, appealed for motorists with footage from the spot at around 9pm to come forward.
She said: "The evidence that you have on your dash-cam could be absolutely vital to finding Sarah."
What will the police be doing right now?
By Peter Kirkham, ex-Detective Chief Inspector
Solving a serious criminal investigation such as a high risk missing person or a murder investigation can be explained using the completion of a jigsaw as a reference point.
We all know that jigsaws come in boxes, with the picture on the lid and all the pieces in the box to put that picture together.
In a criminal investigation, however, things are nowhere near as simple.
There is no picture on the lid (no-one knows what has happened), someone has lost a load of the pieces (pieces of evidence that simply cannot ever be retrieved no matter what the police do) and a load of pieces that do not belong to that jigsaw have been added (evidence gathered which turns out not to be relevant as the investigation proceeds).
Even though Sarah Everard disappeared six days ago, the police will still be very much involved in looking for and securing as much evidence (pieces) as possible.
CCTV searches and viewing will be a major part and we have already heard some information has been found that way. Mobile phone evidence is another major aspect of the investigation as records show not just who Sarah had been in touch with but they also provide a location for the phone when it was used or when it was turned off. Social media is likewise important.
Alongside this officers will be urgently working through her background, identifying and researching friends and family, workmates, etc. to see if they know anything useful or are at all suspicious.
House to house enquiries will be conducted, and the area for these will be extended as more becomes known. Any vehicles identified as of interest will be researched using ANPR records, CCTV footage, etc.
Any identified “scenes” will be searched and examined closely by crime scene examiners (though in a disappearance case there will be less focus on this than in a murder investigation where exact scenes are usually known from the outset).
The investigation will then move on to the assessment of each piece of evidence – how reliable is it, what does it mean, etc. and slowly the pieces will be put together and the picture will start to emerge.
At that stage it is important for officers to keep an open mind – only ruling out possible explanations when the evidence is there to support it.
Hopefully this will identify possible suspects and persons of interest who will be interviewed, arrested, etc. and many new lines of enquiry will be identified.
In short, the officers will be working almost twenty-four hours a day to get all of this done as quickly as possible because it will be assumed that Sarah is still alive to be found even though, as time goes on, it becomes increasingly unlikely.
This initial, frenetic stage will last at least two or three weeks before some calm can be established and the methodical pursuit of lines of enquiry can begin in earnest if the case is still unsolved.
The Met Police is urging anyone who has seen Sarah or who has information that may assist the investigation to call the Incident Room on 0208 785 8244. Information can also be provided to detectives using the Major Incident Portal or by calling Crimestoppers, anonymously, on 0800 555 111.
