Bogus callers claiming to be from Warwickshire Police have been reported calling homes in Budbrooke trying to sell expensive devices over the phone.
A concerned resident reported that they had been contacted by a woman claiming to be part of the crime prevention team at Warwickshire Police.
The woman was offering to sell a device for £99 that would alert friends and family to any intruders.
She then asked for personal details over the phone before trying to arrange a visit to the address for a free quote.
Warwickshire Police has said they would not attempt to contact residents offering products for sale, and has urged anyone who has received similar calls to report them.
Police advise that you should hang up immediately and report it on 101 using another phone, or report it to Action Fraud on 0300 123 2040.
Police have also advised anyone with elderly friends or relatives who may be vulnerable to this scam should talk to them and make them aware.