Dozens of fish are thought to have been killed by pollution in a Devon river, officials have said.
The Environment Agency said it was investigating after it received reports of a chemical entering the River Lew, near Okehampton, late on Monday.
A spokesperson for the agency said about 90 fish had so far died and samples had been taken from the river for analysis to help identify the source of the pollutant.
South West Water said it was aware of the reports and it was supporting the agency with its investigation.