Women in part of Leicester have been warned by police hunting a man who rips off necklaces to stop wearing expensive jewellery when going out.
Police are investigating 15 attacks since September, in which women aged between 40 and 74 years have had their necklaces snatched from them.
The women were not assaulted, although some were injured during the thefts, in the Belgrave area of the city.
Two thefts of necklaces took place on one day last week.
Police have released CCTV footage of a man they are trying to trace. He is described as black or mixed race, around 6ft (1.8m) tall and aged in his 20s.
Detective Constable Nicole Main said: "We have increased patrols in the Belgrave area.
"The best advice we can give residents, particularly women, is to leave your valuable necklaces at home.
"We understand that not everyone wants to do that, so if you want to still wear them make sure they are out of sight of any potential thieves."