CASH stolen in two armed robberies in Hull is being used in businesses across the city.
Police said the stolen notes stained with pink dye are circulating after the two bank robberies this week.
In both robberies, a man told staff he had a gun and demanded money.
Armed police have been on the streets of Hull after the robberies at Yorkshire Bank in Princes Avenue on Tuesday and Natwest in Hessle Road on Wednesday.
Detective Chief Inspector Paul Cunningham, who is leading the investigation, said: "People and businesses are encouraged to be vigilant, especially those with machines that accept bank notes.
"If such notes are located, it is requested that the notes are preserved with minimal contact and the police informed as a matter of urgency.
"Businesses should review their security and CCTV capability to ensure those passing stolen cash are deterred and identified."
Police said various denominations of the stolen cash exist and staining varies from pink edges to saturation.
Det Chief Insp Cunningham said extra police will continue to be on the streets until the robber is identified.
Security at banks across the city has also been increased, with staff warned to be vigilant.
Det Chief Insp Cunningham said: "Police patrols have been strength- ened and redirected to support the banks and businesses who have upgrad- ed their security arrangements."
Police are appealing for people who see the suspect not to approach him and to call police immediately.
After the first robbery, the man was described as white, aged between 30 and 40, about 5ft 10in and of a slim build.
He was wearing a woollen hat, which covered part of his face, dark blue tracksuit bottoms and white trainers.
The suspect in the second robbery was described as a white man, aged between 20 and 30, wearing glasses and with facial hair.
He was wearing black tracksuit bottoms and a black hooded Adidas tracksuit top with red stripes over the shoulder and head.
Anyone with information about the robberies or the stolen cash should call Humberside Police on 101, quoting 101 quoting log number 305 of February in connection with the Natwest robbery or log number 244 of February 5 in connection with the Yorkshire Bank robbery.
Crimestoppers can also be contacted anonymously on 0800 555111.
