"(The) Number of fish killed won’t be known until water clears." Further eyewitnesses claim to have seen "hundreds" of dead fish, with it being confirmed early in 2020 that as many as 8,000 were believed to have been killed by the pollution. A 12-year-old boy was mentioned for alerting people to the dead fish, with a Facebook post from officials saying: "We are very grateful to a 12-year-old boy who removed these fish from a small stretch of the river, put them in his bucket, then staged this photograph for us." The initial reports from the Environment Agency in the aftermath of the reports in 2019 also indicated that the pollution had been "tracked to a probable source" but no cause has yet been identified.