Thames Valley Police is appealing for witnesses after a theft in Banbury at about 11.44am yesterday (Thursday).
A 38-year-old volunteer for the Salvation Army was selling charity newspapers for donations in the entrance of White Lion Walk, High Street.
The offender grabbed the charity bucket containing donations and ran off into White Lion Walk.
The offender is thought to be male, of slim build and over 6ft. He was wearing a grey hooded top with the hood up, a high-visibility vest and black shoes.
Anyone with information about this incident should contact investigating officer PC Ruth Ivins, of Banbury police station, via the 24-hour enquiry line 101.
If you do not want to speak directly to the police you can contact the independent charity Crimestoppers anonymously on 0800 555 111. No personal details are taken, information is not traced or recorded and you will not go to court.