Over the last few weeks, there have been a number of reports of various men knocking on doors in the Luton area saying they are from utility companies wanting to check the meter. An example of this occurred over the weekend, when a man knocked on the door of a woman in her 70s, saying he was from the water board. He made his way into the house, before stealing various items. Detective Sergeant Mark Stewart, from the force’s Operation Maze burglary team, said: “We have received a number of reports over the last few weeks, which we are investigating, but we want to use this opportunity to remind residents to be vigilant against bogus callers. “If you are not expecting anyone to visit you for a product or service, do not let them into your home. Our message is if you're unsure, don't open the door. “Unfortunately the majority of the victims from the reports we have received have been elderly. If you have any relatives or neighbours who would benefit from this information, please make them aware of our advice and tips to follow.