Police are seeking to identify a man who allegedly threatened two members of staff with a metal spanner at Subway on Monks Road in Lincoln.
Nobody was hurt in the incident, which occurred at around 12.50pm today (May 22), but the staff members were left shaken up.
The man was seen leaving the shop with two packets of crisps.
Investigating officers would like to trace and talk to the man pictured to see if he has any information that could assist the enquiry.
If you think you recognise the man pictured, or have any information relating to the incident, call Lincolnshire Police on the non-emergency number 101 quoting incident 198 of May 22.