(CNN)British environmental watchdogs have launched an investigation after thousands of dead sea creatures washed up on beaches in North East England.
Sharon Bell, a Marske-by-the-Sea resident, told CNN she walked the beach near her home every day and had seen a "steady build-up of soft crustaceans," in the past few weeks.
Bell said she went to the beach on Monday morning and was shocked to see "the seaweed was piled high to waist level, but it was absolutely full, and I mean thousands of dead crabs and alive crabs, all varieties, lobsters as well."
She told CNN she visited the beach again Wednesday, only to find the smell was "absolutely terrible," as the piles of dead crabs began to "decompose down."
The UK's Environment Agency told CNN it was working with the Centre for Environment, Fisheries and Aquaculture and North Eastern Inshore Fisheries Conservation Authority to investigate why hundreds of dead crabs have washed up along the shore in the Tees Estuary and neighboring beaches.
"Samples of water, sediment, mussel and crab have been collected," and have been sent for analysis to "consider whether a pollution incident could have contributed to the deaths of the animals," the Environment Agency spokesperson told CNN.
Jacob Young, who represents the seaside town of Redcar in the UK Parliament, tweeted Sunday that the developments along the coats were "deeply worrying."
Bell said she and her husband spent over four hours trying to put as many of the crabs that were still alive and trapped in the seaweed back into the water.
"It's just devastating to see them laying there," she said. "It's saddening because it is such a beautiful area to live in."
Bell added she hoped locals would get answers. "If it is a man-made incident and we've actually done it then obviously we need to make sure it's not going to happen again," she said.