Environmental officers in the North have appealed for public help in their bid to find the polluter responsible for killing more than 35,000 fish in a river in Co Antrim.
The Northern Ireland Environment Agency (NIEA) admitted it has been unable to identify the source of the chemical spill in the Six Mile Water.
Agency staff have narrowed down the possible point of entry into the waterway to two pipes coming from the direction of the Mallusk Industrial Estate.
They are currently carrying out pollution risk assessments on business premises on the estate in an effort to trace the leak.
More than 25,000 trout and around 10,000 coarse fish were killed in the incident on June 18th.
Senior officials from the NIEA met last night with fishermen and other users of the Six Mile Water at a public meeting in Antrim to discuss the impact of the fish kill.
Acting NIEA chief executive Dr Roy Ramsay, who attended the meeting organised by the Antrim and District Angling Association, said he was as anxious as the local community to establish what happened.
"NIEA is frustrated that to date we have not been able to identify who was responsible for releasing the pollutant into the river which caused this fish kill," he said.
"While samples have been collected and analysed and a vast range of substances have been identified, it is still not clear what actually caused this pollution incident.
"This incident has caused great distress to the local community including anglers using the river.
"However someone knows who was responsible. I would therefore urge anyone, whether they are at tonight's meeting or not, to come forward with any information they might have which can help the agency to identify the offender."
Dr Ramsay said his staff had been involved in an ongoing pollution reduction programme within the wider Six Mile Water catchment for a number of years.
PA