Detectives are appealing for people to come forward if they have been approached by a man selling and installing PROSAFE security alarms.
It comes after a fraudster scammed a 90-year-old woman into buying five security alarms at between £400 and £500 when they were worth £4.99.
He visited her home in Harpenden on September 4 and after fitting one of the alarms left the property.
A 50-year-old man from Romford has been arrested on suspicion of fraud by false representation and released on police bail.
Det Con Jason Tinsey from Operation Manhunt said: “We believe that other people in Hertfordshire may have fallen for this scam since the beginning of September and we would be keen to speak to anyone else who has purchased a PROSAFE alarm or had one fitted recently.”
Anyone who has been approached in this way should contact Herts Police on the non-emergency 101 number, or call Crimestoppers anonymously on 0800 555 111.
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