Police are warning residents to beware of fake officials asking for money.
The cold callers are claiming to work for the NHS, the council, and other official organisations.
South Yorkshire Police said some offenders are working together to steal money and possessions, distracting people while their partner goes into people’s homes.
Stazio Machristi, who is from USA and stayed in Upperthorpe, Sheffield, for a month, was a victim of one of these cold callers.
He said while he was approached by a young lady who asked him to complete a survey, someone else entered into the house via his kitchen and took his MacBook Pro, iPhone, and some cash.
The police force reminded people to never give money to bogus officials, and to always ask to see an identification badge of anyone calling at their home.