Police are investigating a fire at a flat above a vacant shop in Sidley Street, Bexhill-on-Sea, which substantially damaged the property and may have been caused by an electrical fault.
The blaze broke out between 5.30pm and 6.30pm on Friday, 20 September.
East Sussex Fire and Rescue crews attended and eventually put out the fire by 11pm. No one was hurt..
The property had not been occupied for a year and officers are keen to speak to anyone who may have information about previous occupants.
Detective Constable Lotte Scott said: "It would help us to know who had lived there or who may have used the premises in the meantime, possibly on a temporary basis."
Anyone with such knowledge, or who has noticed any comings and goings over recent months, is asked to contact officers online or by phoning 101, quoting serial 1193 of 20/09.