Police are appealing information following an assault in the Data Food Store in St Albans Road, Watford, on Thursday.
The incident took place between 8.20pm and 8.30pm when two men became involved in an argument that led to one of the men sustaining a bleeding nose.
Investigating officer PC Caroline Durrant said: “I am appealing for anyone who was in the shop at the time and saw the incident take place to please get in touch as soon as possible.
“Any information you provide could prove to be crucial to my investigations.”
A man in his forties from Watford has been arrested in connection with this incident and has been released on police bail.
Anyone with information is asked to contact PC Durrant via the non-emergency number 101, citing crime reference number C4/14/1439.
Alternatively contact Crimestoppers, the independent charity, anonymously on 0800 555 111.