Warwickshire Fire and Rescue Service could face corporate manslaughter charges over the warehouse blaze that killed four firefighters, police said yesterday.
Police have spent nearly four weeks searching the site of the gutted warehouse in Atherstone on Stour, Warwickshire, and are treating the fire as suspicious.
Speaking about the possibility of the fire service facing charges, Detective Superintendent Ken Lawrence said: "It is possible. We are exploring every possibility and ruling nothing out."
He added the "meticulous" search of the site had so far given no clues about the cause of the fire, saying: "I still don't know what started it. I am erring on the side of caution, treating it as if it was arson, but clearly I would add that I am open-minded about that."
Ian Reid, 44, Darren Yates-Badley, 24, John Averis, 27, and Ashley Stephens, 20, all died after going into the burning vegetable packing warehouse on November 2.
Earlier this week a report claimed the lives of the four firefighters might have been saved if tighter regulations had been in place on the use of foam insulation in roofing panels.
A funeral for Mr Averis, from Tredington, is being held tomorrow, and an official memorial service planned, with a date yet to be fixed.
It is not yet known why the men were sent into the burning building. At the time there had been local reports of migrant workers sleeping in the warehouse, but this was not the case on the night of the tragic blaze, said Det Supt Lawrence. He said: "Anecdotally I understand that that had happened on occasion, but there is no evidence that that had happened that night."
A spokesman for Warwickshire County Council, speaking for the fire service, said the service could not comment on speculation, adding: "This is an ongoing investigation, so it would not be appropriate to comment at this moment."
The investigation at the site of the warehouse fire is ongoing and Det Supt Lawrence said: "The investigation is a massive task. It is very complex and far reaching. It will be several months before we have an accurate picture of what actually took place on November 2."
Chief Supt Paul Mason Brown, who is in charge of operations at the scene, said: "The building front to back is nine bays deep. We are searching a bay at a time.
"We want to find out how the fire was caused, how it spread and how it developed.
"Because of the complexity of the operation we do not envisage the investigation at the site will be complete before the end of January or even longer."
He added that the structure remains unstable and deconstruction work is under way to make searches safe for experts at the site. An air raid-style siren is being used as a safety precaution to warn workers of problems, he added.
Police are continuing to interview warehouse workers and have compiled a list of 400 people who were at the site in the days preceding the fire. They have brought in translators to help work through the number of workers who speak foreign languages.
The Fire Brigade Union in the West Midlands yesterday said it was carrying out its own independent inquiry into the fire, and hoped to publish the results in January.