Police in Waltham Forest are warning the elderly and vulnerable against falling victim to courier fraud after two women were targeted on Monday.
The first victim, a 90 year-old woman from Walthamstow received a phone call from a suspect claiming to be a police inspector.
He told her he was investigating an on-going fraud case and cash from her bank account needed to be forensically tested for finger prints.
The suspect then turned up at her address and took £10,000 cash which had been drawn out of her life savings.
In the second incident, the suspect claimed to be detective constable George Daley but before he could continue the scam, the 85 year-old woman from Leytonstone hung up the phone and notified the police.
The Victim recognised the call as being part of a scam and hung up the telephone.
Cases of courier fraud are becoming more frequent with criminals finding new and sophisticated ways of duping the vulnerable and elderly community into handing over cash.
Residents are being warned not to give out any personal information over the phone especially banking information such as PIN numbers, or physically handing over bank cards to a courier or taxi driver.
"The effects of becoming a victim of crime run far deeper than a loss of property or cash.
"These crimes represent two ladies of senior years who now have the unenviable task of coming to terms with being targeted by a fraudster.
"Courier fraudsters put a huge amount of time and effort into being convincing because the pay-off can be immense.
"We want people to question even truly genuine sounding calls and, most importantly, remember police and banks will never ask for your PIN or bank card, so you should never give these away," said detective superintendent Kevin Baldwin.
They are advising residents to hang up the phone if these details are requested and to call the police on a different line at least five minutes after the suspected hoax call.
Superintendent Baldwin added: "My officers, working with our borough partners, will continue to pursue these unscrupulous criminals while also raising awareness among those people who could be potential victims.
"Please help us by making sure that anyone you know who may be vulnerable to courier fraud is aware of this scam."
If you have information about this or any other crime please contact police by dialling 101 or call Crimestoppers anonymously on 0800 555 111.