Detectives believe this man could have information that may assist their enquires into an incident in Tesco in Claughton.
A report was received at around 12.45pm on Thursday 20 June that staff at the Tesco Express store on Upton Road had been threatened by a man they had detained.
The man was stopped as he was suspected to be shoplifting, and handed over household cleaning products. But he then produced a knife and made threats to staff before running away.
Inspector Bernard McHugh said: “It was completely unacceptable for supermarket staff to be subjected to this ordeal while they were just trying to carry out their job, and we are determined to find the man responsible and bring him to justice.
“We believe the man in this image could have vital information If you recognise the male in this image, and we appeal to the man or anyone who thinks they might know him to contact us.”
Anyone with information is asked to contact Merseyside Police social media desk via Twitter @MerPolCC or Facebook Merseyside Police CC. You can also call 101 quoting incident reference 19100323197 or contact the independent charity Crimestoppers anonymously, on 0800 555 111 or via their online form at: https://crimestoppers-uk.org/give-information/give-information.