Police have revealed that the man was arrested yesterday morning.
They say that he is in custody, and that a criminal investigation has been launched.
It took 25 firefighters to control the fire, which began just before 5 am on Monday morning.
Four fire engines attended the scene, along with an aerial platform.
Damage was caused to neighbouring buildings, and neighbours had to flee from their homes, but no one was hurt.
Photo credit: Sean Henstridge