An arson attack could be the cause of a fire at an industrial unit complex that detectives suspect was being used to house a drug lab.
Police are also searching for two men spotted on the roof of the building who have not been found despite a search of the complex.
Emergency crews including Fire and Rescue NSW and NSW Police were called to the units at Revesby, in Sydney's southwest, just after 5am on Wednesday.
Firefighters extinguished a blaze that damaged the first floor and left smoke and water damage to the ground floor of one unit.
On Tuesday, police had secured the building as a crime scene and were investigating whether the units were part of a drug lab linked to an alleged organised crime syndicate.
