A rapist claimed to work for the council before attacking a woman at her home in Benhilton.
Police have released an e-fit of the attacker who knocked on the woman's door and told her he worked for the council before going into the property and raping her on Saturday evening.
The attacker is black, in his 40s and about 5ft 4in tall. He had a round face and a bald head and was wearing a blue round-necked fleece-type jumper with a red or orange logo on the breast. The victim is in her 40s.
Police are keen to find out of anyone else in the area was visited by a man matching the description or saw anything that could help them in their enquiries.
Officers have urged people to be vigilant and not allow unsolicited callers into their homes unless identification is shown. If you are suspicious, call police on 999.
Anyone with information can call police on 101 or the charity Crimestoppers on 0800 555 111.