A police squad set up to target thieves who prey on the elderly or vulnerable have issued a fresh warning.
Cleveland Police started Operation Strongbow in June 2003.
It said there had been an increase in distraction burglaries and incidents involving jobbing builders in parts of Teesside in the last few days.
There have been reports in areas of Middlesbrough and Stockton and police are warning people not to let cold callers into their homes.
Police said there had been three incidents this week in the Park Lane, North Ormesby and Berwick Hills areas of Middlesbrough where people had called at the homes of elderly people asking for water.
They have entered the house and made off with cash.
Other excuses have been to ask for a pen and paper and asking residents to turn off electricity and gas.
They said the Middlesbrough and Stockton areas had also been hit by jobbing builders.
In one case a man was given a £7,000 bill for a small amount of work and in Stockton a man has been knocking on elderly people's doors offering to fix the tiles on their roofs and then asking for more than was originally agreed, once the work is done.