A spokesperson from Avon Fire and Rescue Service told the BBC that “extensive damage and subsequent demolition works meant it could not accurately determine the origin and cause of ignition.”
The property was partly demolished following the devastating fire which caused the building to collapse onto the A4018 dual carriageway.
Avon Fire and Rescue Service (AFRS) were originally called to the property at 1.17pm on 17 July, which was declared a “major incident” at the time.
Firefighters in breathing apparatus entered the building but were withdrawn due to the “extensive” fire that had spread quickly through the building and caused structural damage.
In a Twitter post the AFRS said crews “worked hard” with the resources available to control the fire and prevent it spreading to neighbouring businesses. The fire service also asked residents in the local area to keep their doors and windows closed due to the smoke from the incident.
Avon and Somerset Police said at the time: “A major incident was declared shortly after 5pm, following the fire at the Premier Inn, Cribbs Causeway. This is due to the level of resources required by emergency services at a time when they are already stretched following protest activities in Bristol city centre this week.”