Police investigating the murder and kidnap of oil executive Carole Waugh have arrested a woman on suspicion of conspiracy to defraud.
The 61-year-old is in custody at a south London police station, Scotland Yard said.
Ms Waugh, originally from Durham but living in London, was reported missing by her family on May 7 after she had not been seen since 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.
The 50-year-old's body was found with a single stab wound inside the boot of a blue VW Golf in a garage in Lime Court in New Malden, south west London, on August 2.
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.
At least three women have tried to pose as her since she vanished, police said.
A total of 11 people have been arrested so far in connection with the inquiry into her death.
Nicholas David Kutner, who was arrested last week, has been charged with conspiracy to commit fraud.
The 47-year-old, of no fixed abode, faces two charges relating to renting Ms Waugh's property at Tressard Court and another of unlawfully withdrawing funds from her bank account.
He is also accused of pretending to be Ms Waugh's brother Chris in an alleged attempt to sell her home.
Kutner is in custody and is due to appear at Southwark Crown Court on Monday.
A second man was arrested by police on suspicion of murder on Thursday and is still being questioned by police.
Rakesh Bhayani, 40, of Chamberlayne Avenue, Wembley, also faces three charges of conspiracy to commit fraud by false representation worth about £280,000, following transactions associated with Ms Waugh's identity and is due in court next month.
