Police are hunting two conmen after an elderly woman was swindled out of more than £24,000.
The 71-year-old Londoner received a phone call on December 6 from a man claiming to be a police officer.
He told her the police needed her help in an undercover sting operation which require a financial contribution.
Southwark Police said the victim handed over £5,000 worth of Euros in her first encounter with the man, and £7,000 to another unseen man on a separate occasion.
In total, the victim ended up handing over more than £24,000.
The first suspect is described as an Asian man, standing at around 5ft 8ins, and in his 20s.
DC Michael Esangbedo of Southwark CID, said: "This was a cruel and heartless deception practised on a vulnerable, elderly woman.
"These men have clearly targeted the victim and I have no doubt that unless they are arrested they will continue to prey on the elderly and vulnerable.
"These men need to be caught and I would ask anyone with information to contact police or Crimestoppers immediately."
Police have released an image of a suspect they believe to have been involved in the incident.
Any witnesses or anyone with any information is asked to call police on 101.
