A woman drowned after walking to an island to read some books and getting caught there by the incoming tide.
Christine Plummer became cut off from the mainland when the tide covered a shale causeway and cut her off.
Ms Plummer (40), who was originally from Derry, but had lived in Buncrana, Co Donegal, for many years, was found dead on the shoreline close to Rockstown Harbour on the Inishowen Peninsula at around 5.30pm on Monday evening.
It is thought the part-time student decided to wade back through the water but got into difficulty when she entered a deep hole and was unable to reach dry land 300 metres away.
Her body was found in shallow water and brought to shore by a passer-by.
Ms Plummer's car was found nearby and it was initially thought a child had been with her, as a woman of a similar description had been spotted with a youngster earlier.
However, after an extensive land and sea search, the PSNI in Derry confirmed that no members of Ms Plummer's family were missing.
Spokesman for Lough Swilly Lifeboat, Joe Joyce, said Ms Plummer could have survived if she had taken another route off the island.
"She was unfortunate in that we think she made her way back through some deep water and this is why she probably got into difficulty," he said.
"If she had taken the long way around, then the water is not as deep and she could have waded through it. There are very heavy spring tides at the moment and she would have found herself cut off very quickly."
Ms Plummer was very popular and very well-liked in the area. She loved photography and was also involved in the local historical society.
During a search of the area, books on archaeology and nature, believed to belong to Ms Plummer, were discovered.
Buncrana town councillor Ciaran McLaughlin, who knew Ms Plummer, said he was very saddened to hear of her death.
"Chris was a lovely girl – a very sweet person," he said.
"She was very inoffensive and had been living in Buncrana for what must have been up to 20 years.
"She loved nature and photography and was forever out walking and taking pictures."