A fraudster claiming to deal with damp problems is targeting homes in Sheffield, according to police.
South Yorkshire Police have warned that the young man has been approaching residents in their homes, claiming to be from a company.
The man then attempts to get invited into their homes by claiming to deal with damp problems.
However, officers have warned that residents have been asked to provide photographs and other identity documents which he then photographs.
The man, described as an Asian male in his early 20's, has been reported in the Wybourn area but police said he could be travelling around Sheffield.
A spokesperson said: "Please be aware of a suspicious male claiming to be from a company.
"He is trying to get invited into properties by claiming to be there dealing with damp problems. The male does not have any official identification.
"He is being invited into properties and has been asking to photograph passports and other identity documents belonging to the occupants.
"This has been in the Wybourn area of Sheffield but he could be travelling further a field.
"Do not let this male into your property and please call the police on 101 as we are keen to speak to this male.
"Described as an Asian male, early 20s, smartly dressed and sounding "professional/convincing". Using a large black saloon car.
"If you know somebody who is vulnerable, please warn them to be aware of this male."