An elderly couple were tricked into handing over £8,000 by a “deplorable” fraudster posing as a police officer.
The man first telephoned asking the pair to withdraw £40,000, but their bank became suspicious and blocked it.
Police said the next day the offender called again and convinced the woman to hand over £8,000 to a “courier” on Wesleyan Row, Clitheroe.
He told the man and woman in their 80s and 90s he was Scotland Yard detective investigating a fraud case.
Police are appealing for help from anybody who was in the area of Trinity Methodist Church on Wesleyan Row at about 16:30 GMT on 30 October, especially if they have dash cam or CCTV footage.
The offender is described as mid-20s with dark hair, a dark complexion and clothing.
Det Con Heather Kerr said: “This is an utterly deplorable offence made all the more callous and tragic by the fact that the offenders groomed the woman into thinking she was assisting a serious police investigation by handing over money.
“Such damage was done to her trust that even when I spoke to her I had to be accompanied by another colleague in uniform.”