The Environment Agency has identified the source of the pollution which contaminated a Wirral lake last September and caused the deaths of thousands of fish, according to the Wirral News.
A spokesperson for the organisation told the newspaper that it is now working to trace the source back to its point of contamination, but was unable to comment further.
In September 2009, users of the Arrowe Country Park discovered a large number of fish floating dead on the surface or gasping for air.
Despite the swift installation of oxygen pumps, much of the harm had already been done, the publication explained.
Malcolm Gillies, chairman of the Association of Wirral Angling Clubs, commented that those involved are hopeful of bringing a prosecution.
Speaking to the news provider, he said: "It's down to one thing, if the person who did it owns up to it."
According to Environment Agency statistics, inert materials and waste were the most common pollutants in 2008 and were found at 13 per cent of all serious water pollution incidents.