Police say a fire which tore through a factory in Lenton was started after it was ransacked by burglars.
The building on Faraday road was set alight just after midday on Wednesday, creating a plume of smoke which covered the area.
Detectives now believe thieves broke into it and stole clothes before the fire, which almost destroyed the building before it was brought under control.
Police are still trying to trace those connected with the property, which used to be known as S&P Casuals but was not being used regularly at the time of the fire.
A Notts Police spokesman said: “While the owner of the building has been in touch, the current named leaseholder has yet to be traced and is now being sought as a victim of crime.”
Two people, an 18-year-old man and 16-year-old boy, have been arrested on suspicion of arson and bailed pending further enquiries.
Two other boys, aged 16 and 17, have been arrested on suspicion of burglary and also bailed pending further enquiries.
Anyone with information about the leaseholder or the fire is asked to contact police on 101, quoting incident 301 of April 27.
Alternatively call Crimestoppers anonymously on 0800 555 111.