Staff at an off-license on Commercial Road were threatened by a man with what appeared to be a small handgun or imitation firearm on Halloween, police said.
Between 10pm and 11pm on October 31, a male is said to have entered Coleman's Confectioners and threatened staff with the object in an attempt to steal some cigarettes and cash.
Nothing was stolen and no injuries were reported.
The man ran off in the direction of Mayflower Theatre.
Police are looking to speak with a man in connection to this investigation.
READ MORE: P&O Cruises: Norovirus, Covid and tuberculosis recorded
He is described as black, about five foot ten inches tall, aged between 18 and 25 years old and with a slim build.
Hampshire Constabulary said: "We are issuing an image of a man we would like to speak to in connection to this investigation.
"He is wearing a black coat with grey fur in the hood, with an orange hooded jumper underneath the coat.
"If you know who this man is, please contact police immediately."
Police are also looking to identify several people who were in the area at the time and may have seen something - they have issued two further images of potential witnesses who they would like to come forward.
Anyone with information should call 101 quoting reference 44240474974.
Alternatively, you can report online at https://www.hampshire.police.uk/tua/tell-us-about/cor/tell-us-about-existing-case-report/
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article