Avon and Somerset Police have released a CCTV image of a man they want to speak to in connection with the SWX nightclub fire in Bristol.
The nightclub fire took hold at the venue in Nelson Street in the early hours of Tuesday 13 July.
At the height of the incident there were 20 firefighters working to tackle the blaze, which was extinguished at around noon.
The fire came just days before the club was officially due to reopen after months of closures because of the coronavirus pandemic.
An investigation had originally suggested the cause of the fire was deliberate, but upon further inspection it was officially changed to 'unknown'.
Police have now revealed an accelerant was believed to have been used to start the fire.
Detective Inspector Tola Munro said: "As well as causing substantial fire damage to the venue this attack has cost the owners a significant amount in lost revenue which only adds to the upset such an incident causes.
"We’re taking the incident extremely seriously and have carried out a large number of enquires since it happened, including trawling through hours of CCTV footage from the local area."
The scene at the nightclub in Bristol
The club's owner Dominic Madden said at the time of the blaze: "It saddens me and all our loyal music fans that just a matter of days before the full reopening a fire has delayed the much anticipated return to live music and club events.
"If it was not for the heroic efforts of the Avon Fire and Rescue Service with the support of Avon and Somerset Police, the damage would have been much worse and I would like to thank them all for their help."
Anyone who can help identify the individual is asked to call the police 101 and provide the call handler with the reference 5221157462.