Human remains found at a burnt out mill in Oldham indicate there were at least two victims of the fire, police have said.
Specialist officers began searching Bismark House Mill on Saturday after demolition workers discovered human remains.
The site was part-destroyed in a fire on 7 May, but police said at the time that the premises were empty.
Greater Manchester Police are now looking into reports they received on Thursday last week that four Vietnamese nationals are missing from the area and may have been involved in the fire.
Detective Superintendent Lewis Hughes said: “We are carrying out an extensive search of the remnants of the mill to ensure any further human remains are recovered in a way which is respectful to both the deceased and the bereaved.
“Meanwhile, our major incident team are continuing to liaise with partner agencies to ensure potential family members in Vietnam are fully informed and supported.
“Though we’ve now recovered human remains to suggest that at least two people were in the mill during the fire, we remain conscious of the report we received, on Thursday July 21, that four Vietnamese nationals were missing and may have been involved in a fire.
“Alongside the search and recovery efforts, extensive enquiries are being carried out to establish the full circumstances surrounding the fire.
“Any criminal offences identified as part of this will be progressed immediately and appropriately.”
The mill is a multi-occupancy warehouse where it took four days for firefighters to put out the blaze two months ago.
GMP has now been referred to its Professional Standards Branch to review how the incident was dealt with in light of the report of the missing people.
Police are urging anyone who is concerned about a missing loved one or who has information about the circumstances surrounding the fire, including activity at the premises before 7 May, to contact the Major Incident Room on 0800 051 4675, for UK callers, or (+44) 0207 459 4500, for international callers.
Information can also be submitted via the Major Incident Public Portal at mipp.police.uk or anonymously through Crimestoppers on 0800 555 111.