The man arrested on suspicion of arson with intent to endanger life after the fire at Pink Punters nightclub has been released on conditional bail.
Police have said the 51-year-old from the new city has been released while inquiries continue.
The blaze at Pink Punters followed a fire at a neartby church a day earlier.
"At the moment we are keeping an open mind and investigating the incidents in conjunction with each other due to proximity in location and time," a spokesperson said.