The bank accounts of a wealthy businesswoman who has been missing for three months have been accessed fraudulently to the tune of hundreds of thousands of pounds.
Suspicious activity peaked in the past 10 days, and detectives are seriously concerned for the safety of Carole Waugh, 50.
They believe Waugh, an oil industry executive, may have been abducted, and forced to reveal her pin numbers.
At least three women, and an unknown number of men, have used the identity of Waugh, whose family reported her missing on 7 May when she had failed to contact them for more than three weeks. Her lack of communication was entirely out of character, they said.
Two women caught on CCTV cameras at the Westfield shopping centre in west London on 13 July were arrested on Tuesday after detectives appealed for the public's help in the hunt for Waugh, from Marylebone, central London.
The description of a third woman who has also impersonated Waugh has been given to detectives by a witness. But officers believe other individuals have also taken her identify in order to access her bank account.
An extensive forensic search of her flat in Harrowby Street is now being carried out.
Detective Chief Inspector John McFarlane, of the homicide and serious crime command of Scotland Yard, who is in charge of the case, said there were fears for Waugh's safety.
A sighting of a woman thought to be her on 4 May has not been confirmed, he said.
"There is highly suspicious activity involving impersonation fraud of a very high value in relation to her which gives me great concern for her wellbeing," McFarlane said.
"The last confirmed contact with her was 17 April. Since Carole was last seen at least three women have been involved in impersonating her at a number of different venues. I also believe there are a number of men involved in the fraud."
Waugh worked in the oil industry in Libya during the Gaddafi era until 2008. Her disappearance was initially dealt with by local uniformed officers at Westminster as a missing persons report.
Officers visited her flat, but there was no reply. Activity on her bank accounts in the past 10 days raised the concerns of police, and the homicide and serious crime command took over the case on Thursday. Within hours of analysing the suspicious activity, detectives had serious fears for her safety.
Waugh is not understood to have a large circle of friends in London, as she had worked abroad for some time. She was planning to celebrate her 50th birthday in June with a family party. Her mother Margaret, 78, said: "I'm very worried at present. I am not very good at all. We are all concerned for her at present."
She has said that her daughter used to call her a couple of times a week, but when she did not hear from her for three weeks she contacted her son and realised something was seriously wrong.
Margaret Waugh told the Daily Telegraph: "She always went running at night. I gave her a device to carry, an alarm, but she never bothered with it. She said there was nothing to worry about."
McFarlane said he was investigating a missing person, but had growing concerns and nothing he had uncovered in the past two days had alleviated those worries.
He said it was out of character for her not to be in contact with her family. "She was about to celebrate her 50th birthday in June, and as she had arranged her brother's birthday he was going to do the same for her. But she has not been in touch at all," he said.
Five other people have been arrested and bailed in connection with the case. A sixth individual, Rakesh Bhayani, 40, of Wembley, north London, appeared at Westminster magistrates court on Tuesday charged with three counts of conspiracy to commit fraud by false representation.