Residents in Penylan, Roath and Cyncoed are concerned because people’s house are being tagged with spray paint.
The new spray paint codes in Cardiff use red spray paint to symbolise expensive electronic goods and yellow to indicate that there are expensive dogs or litters of puppies to be stolen.
There are also codes to indicate houses which have been left empty and those where vulnerable residents live.
South Wales Police say they are linking the taggings to a recent increase in burglaries across Cardiff.
They are encouraging people to be vigilant and are treating the markings as suspicious.
The police advise calling 999 or Crimestoppers as a way of preventing this issue.
Joanna Young, who lives in Cyncoed, has had her house as well as her neighbour’s tagged with spray paint.
She says they’ve had to install CCTV.
“This is not ideal but in this situation it just makes me feel a bit easier as I’ve got three dogs as well.
“Hopefully the CCTV will stop people from targeting the addresses”.
Other people whose house have been tagged say that the spots of coloured spray paint outside their houses are making them paranoid and worried to leave the house.
Councillor Bablin Molik says the markings are raising fears in the area.
“Cyncoed and Lakeside have previously been targeted for burglary.
“Any such marking should be reported to the police by ringing 101, take a picture of the marking and record it if you are suspicious of any burglary attempts.
“Be aware of each other in the neighbourhood”.
