Bogus “water board” officials stole £3,000 cash from a 70-year-old man in Portslade on Monday afternoon.
The two conmen called at the man’s home in Mill Lane just before 4pm.
After he let them in, one distracted him while the other stole his money, savings book and cheque book.
The same pair attempted to carry out a similar distraction burglary in Church Road, Portslade, at about 1pm on Monday.
They said that they had come to put blue dye in the water system to test it.
The married couple in their mid-sixties who live at the address asked to see proof of identity.
The conmen left empty-handed saying that they would return although they didn’t.
Sussex Police issued a warning to be careful about allowing in unannounced visitors.
Detective Inspector Clare Shiel said: “These are two more examples of the way in which elderly people can be preyed upon by callous thieves.
“Bogus callers target older people – the average age of their victims is 81.
“Sixty per cent of victims are women and the vast majority live alone.
“We applaud the actions of the Church Road couple who did exactly the right thing and kept them out.
“Remember, when you hear that there is someone at the door, take your time – a genuine caller will wait.
“Check your doors are locked – offenders can come in pairs.
“One will enter the back while the accomplice distracts you at the front.
“Look and see who is there using the door viewer or nearby window.
“If at all in doubt, keep them out.
“If you do decide to open the door, apply your door chain or door bar.
“If you are not happy with the caller and your suspicions are aroused, call Sussex Police on 0845 6070999 or in an emergency dial 999.”
