SEA ISLE CITY — Officials know where in a 54th Street duplex last week’s massive fire started but have not determined the cause of the blaze that killed one woman and one dog.

Police Chief Thomas McQuillen said he could not specify the area of origin because it could be subject to change in the ongoing investigation.

Meanwhile, an autopsy was performed on the victim, Marie Zielinski, 89, on Dec. 1. According to officials, Zielinski’s cause of death is tentatively listed as smoke inhalation, pending toxicology reports.

According to a news release from the city, members of the Cape May County Prosecutor’s Office, Cape May County Fire Marshal’s Office, New Jersey Fire Marshal’s Office and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are still investigating.