A woman aged in her 80s was targeted by two doorstep crooks who pretended to be working for the council.
They tricked the elderly lady, of Waterside, Kings Langley, into letting them in to check the water pressure on Wednesday and then persuaded her to hand over £30 for a new valve.
After they had left the victim then realised that more than £150 had been stolen from her purse.
Det Con Jon Leak, from the specialist team Operation Manhunt, which investigates distraction burglaries, said: “The victim clearly thought there was an immediate need to let the men into her property. This is the way these criminals operate - they create a sense of urgency and are extremely convincing.
“I would like to appeal to anyone who was approached that day by these two men. Did they call at your door? Did you see them in the area acting suspiciously? Did you see any suspicious vehicles?”
The first thief is described as a white man of slim build, aged around 40, with mousey brown hair and between 5ft 6ins and 5ft 7ins. He was wearing a pale grey T shirt, jeans and black trainers. He was clean shaven and spoke with an English accent.
His accomplice was also white, aged around 35, the same height as the first man, with darker hair and a larger build. He had some facial hair and was wearing similar clothing to his pal but with lighter trainers. He also spoke with an English accent.
Det Con Leak said: “I’d also remind people not to open the door to unexpected callers. If you are not expecting anyone and you don’t recognise them, don’t let them into your home.”
Always call 999 if you suspect a crime is in progress.