A man suffered minor injuries after being assaulted and having a noxious substance thrown at him.
The 49-year-old had been walking in Eleventh Avenue, Blyth, at 12.30am on Wednesday, November 11, when the robbery happened.
He was assaulted by three men who threw the substance at him before making off with his bag.
The man was taken to hospital and received hospital treatment for what are believed to be minor injuries.
The three men are described as being aged in their 20s and were wearing tracksuits.
Acting Chief Inspector Dave Harris said: “We appeal to anyone who may have been in or around Eleventh Avenue in the early hours of this morning and who may have witnessed the incident to contact us.
“Enquiries are underway and we have officers in the area carrying out enquiries and offering reassurance to people.
Anyone with information should contact police on 101, extension 69191, quoting log number 29 11/11/15 or ring the independent charity Crimestoppers on 0800 555 111.