It was reported a black Engwe L20 e-bike was stolen from a bike rack in the underground car park of Castlepoint shopping centre at around 2.35pm on Monday, March 9.
Officers have now released a photo of a man they are looking to identify in connection with the incident.
Police Community Support Investigator Mike Cannings, of Dorset Police, said: “We are carrying out enquiries into this theft and I am issuing images of a man we would like to identify.
“I would urge anyone who recognises him to please make contact with us.”
Anyone with information is asked to contact Dorset Police online or by calling 101, quoting occurrence number 55260037534. Alternatively, independent charity Crimestoppers can be contacted anonymously online using its website or by calling Freephone 0800 555 111.