Suzanne Pilley vanished more than a week ago in Edinburgh
Police searching for an office worker who went missing in Edinburgh have enlisted the help of specialist consultants.
Suzanne Pilley, 38, set off for her job on Tuesday 4 May but never arrived.
A team from the National Policing Improvement Agency (NPIA) is now supporting the investigation into her disappearance.
Lothian and Borders Police said they had "grave concerns" for Ms Pilley's safety.
The NPIA, which supports high profile investigations across the UK, will provide access to specialist equipment and techniques.
Iain Livingstone, assistant chief constable of Lothian and Borders Police, said this type of investigation was rare and described NPIA's support as "invaluable".
He said: "Obviously, we now acknowledge that we have grave concerns for Suzanne's safety, and we cannot rule out the possibility of a criminal act.
"The dedication of all officers assigned to this inquiry is commendable, with a high volume of work already completed, and a vast number of investigative avenues exploited.
"In saying that, however, any inquiry can only benefit from the expertise of advisors from around country."
Friends of Ms Pilley have set up a Facebook page to help in the search, which subscribers to the social networking site can access by searching for her name.
Earlier efforts to trace Ms Pilley include a huge screen positioned in St Andrew Square, which displayed CCTV footage of her on the way to her office.
Ms Pilley boarded the no 2 bus at Stevenson Drive at 0820 BST, getting off at 0832 BST and changing to the no 4 bus at Dalry Road, opposite Caledonian Terrace.
She got off the bus at Jenners department store in Princes Street at 0848 BST then went into the Sainsbury's supermarket near St Andrew Square, but failed to report to her work in Thistle Street.
The last confirmed sighting of Ms Pilley is on CCTV footage outside Sainsbury's at 0851 BST.
Ms Pilley, from the Stenhouse area of the city, is described as being white, 5ft 4ins tall, of slim build and short, light brown hair shaped into a bob.