Police investigating the death of oil executive Carole Waugh have made two further arrests, Scotland Yard said.
A Metropolitan Police spokesman said a 55-year-old man and a man of 39 were arrested in central London yesterday in connection with conspiracy to commit fraud.
Both have been bailed to a date in early September, pending further inquiries.
Miss Waugh, originally from Durham but living in London, had not been seen by her family since mid-April.
Her body was found with a single stab wound inside a car at a garage in Lime Court, New Malden, south-west London, on August 2.
Miss Waugh was reported missing by her family on May 7. They last saw her at a family party in mid-April.
She had lived and worked in Libya for a number of years, but returned to London in 2008 and would regularly visit relatives in Durham and Cumbria.
Her former boss, Stuart Anderson, told journalists she had fled Libya after being threatened by someone in Colonel Muammar Gaddafi's regime, but a Scotland Yard spokesman said inquiries are focused on London.
Detectives said she met men through a variety of internet sites, including dating websites, and they were investigating the possibility that she might have been an escort.
So far, a total of 13 people have been arrested in connection with the inquiry into her disappearance.
At least three women have tried to pose as her since she vanished, police have said.
Her flat is in an affluent part of central London and her brother Chris previously said she was "very frugal and careful" with money.
Two men have been arrested on suspicion of murder.
Rakesh Bhayani, 40, of Chamberlayne Avenue, Wembley, north west London, has been bailed to return to police in mid-August.
He is due to appear in court next month on three charges of conspiracy to commit fraud by false representation worth about £280,000, following transactions associated with Miss Waugh's identity.
Nicholas David Kutner, 47, of no fixed address, who was arrested on suspicion of murder and kidnap last week, is also due to answer bail later this month.
He faces two charges relating to renting her property at Tressard Court and one of unlawfully withdrawing funds from the 50-year-old's bank account.
He is also facing a fraud charge after being accused of pretending to be Chris Waugh, Miss Waugh's brother, in a bid to sell her London home.
Scotland Yard has appealed for information about the blue Volkswagen Golf in which Miss Waugh's body was found, which has the registration number W466 NHL.