Staff of Nice N Naughty adult shop in Liverpool City Centre reported that a man wearing a red dress, wig, grey cap and white gloves had entered the store on Colquitt Street and produced a black handgun, which was used to threaten a member of staff on Sunday.
Merseyside Police said staff reported that the man snatched money from the counter and left the shop after a brief struggle.
The force has issued CCTV images of a man they wish to speak to following the raid which took place at around 5.40pm.
Detective Inspector Steve McGrath from Liverpool CID said: “We are keen to speak with the man pictured to assist us in our inquiries.
“The staff at the shop were thankfully unhurt but understandably distressed to be threatened with what had the appearance of a firearm, regardless of whether it was real or fake.
“I would appeal to anyone in the Colquitt Street area around 5.30pm who saw a man dressed as described and acting suspiciously to contact police at once.
“We have spoken with the owners and staff to offer reassurance but I want to assure all businesses that we will do everything possible to identify this offender and bring him to justice, and ensure Liverpool City Centre is a safe place to live, work and visit.”