Police say they would like to speak to three males seen running from the Old Mill building in Crumlin on Saturday night shortly after a fire broke out.
Arsonists are being blamed for the blaze which caused extensive damage to the landmark building based on the Mill Road, around 9.30pm.
Four pumping appliances and an aerial machine were used to deal with the blaze which was started on the ground floor and also spread to upper floors.
The exact cause of the fire has yet to be determined.
Police are appealling to witnesses who may have seen anyone acting suspiciously in the area or who has any information about the incident to contact them on the non-emergency number 101.
If someone would prefer to provide information without giving their details, they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.
The fire comes as the police in Antrim were asking local parents for their support in tackling increased reports of anti-social behaviour in and around the area of Crumlin Glen.
Local police say are concerned at the numbers of young people who gather in the area of Crumlin Glen in the evenings and at weekends.
A meeting organised by the Antrim Policing and Community Safety Partnership was held in response to community concerns about anti-social behaviour in Crumlin Glen at Crumlin Integrated PS.
Chief Inspector Natalie Wilson, Antrim Area Commander,stated: “We are aware of the impact anti-social behavioural issues in the area have on the local community of Crumlin and we are working tirelessly to tackle the problem.
“We take a very pro-active approach working in partnership with our partner agencies and local community groups.
“We have increased patrols in the area at peak times and we will continue to work hard to tackle the issues and reduce the number of incidents.
“We will exploit all opportunities to address these problems however to do this we require the help and support of the community.
“We are keen to get the message out to parents to help us by ensuring you know where your children are when they are out and about in the evenings.
“Please make sure they know not to become involved in underage drinking or anti-social behaviour.
“On top of the risks they are taking by breaking the law, it’s important that they know that alcohol can also leave them vulnerable and can put their personal safety at risk.”
The mill building has a long history. In 1765 Rowley Heylands built one of the first industrial flour mills in Crumlin.
These mills greatly encouraged the growing of wheat in the area and the village began to prosper.
The Government regarded the mill of such importance (five storeys high, powered by three water wheels) that they built warehouses and encouraged extensive wheat-growing in the district.
By 1815, the tillage in the area had grown to 24 per cent under wheat alone.
For over a hundred years Crumlin’s success was linked to the flour mills and then the Ulster Woollen Co. Ltd, which manufactured flannels, worsted coating, fingering and kitting yarns, and the famous Lough Neagh Tweeds.