Norfolk Police is urging residents to report any suspicious behaviour after rogue traders targeted Harleston on Thursday.
They said people were attempting to sell gravel for driveways in the town.
Rogue traders trick people, often by pretending to be builders and charging very high prices for unnecessary or poor quality work.
Norfolk Police offers advice on how to avoid becoming a victim of rogue traders. These include locking your back door before answering the front door, always ask for proof of identity, and never pay for work until it has been completed.
If you notice any suspicious activity, contact police on 101, or Trading Standards on 03454 040506.
For more police advice on rogue traders and cold callers, visit www.norfolk.police.uk/advice/home-safety/rogue-traders-cold-callers