Stormont has been declared a "crime scene" over the ongoing environmental crisis at Lough Neagh.
A symbolic citizens’ arrest of a member of Northern Ireland's parliament was staged during a demonstration calling for immediate action to address the issues facing the lake.
It was blighted with blooms of blue-green algae for the third summer in a row.
The cause has been put down to an excess of nutrients from a number of sources, including waste water, septic tanks and agriculture, exasperated by climate change and the invasive species Zebra Mussels.
Minister for Agriculture, Environment and Rural Affairs Andrew Muir is implementing a Lough Neagh Recovery Plan.
However, Director of Friends of the Earth Northern Ireland James Orr said that all government departments are responsible.
Activists also called for an independent environmental protection agency for Northern Ireland, community ownership of Lough Neagh with the rights of nature enshrined, a citizens’ assembly for the lake, a "moratorium on all factory farms and sand dredging" and urgent investment in waste waster systems.
Addressing those gathered, Mr Orr declared Parliament Buildings and the Stormont Executive inside to be a crime scene.
"We have a lot of merit in saying that. First of all, under the Wildlife and Natural Environment Act, if any public department causes damage to an ASSI (Areas of Special Scientific Interest), it shall be guilty of a criminal offence.
"If we look at all the departments responsible for the death of Lough Neagh, what we would say is that Lough Neagh isn’t dying of manslaughter, it is being murdered by a whole range of different government departments."
Mr Orr described the lake as "our most precious natural habitat and cultural jewel", but said that waste water is being dumped in it and sand dredged from it.
"There are lots of things that this executive could do, the fact that they’re not doing them, and they’re deflecting us from the real issues which are sand mining on an industrial scale, the defunding of NI Water and most important, DAERA should be (hanging their heads in shame) that the agricultural strategy which will demolish family farms and replace them with factory farms is still going ahead.
"We’ve had enough and we’re declaring Stormont a crime scene," he said.
