A group of teenagers stopped to swim in the water while cycling in the area – with one getting into difficulty while swimming and another while trying to help him.
Two 16-year-old boys have died after getting into difficulty in a lough in Derry.
The drowning unfolded at Lough Enagh on Monday evening when a group of teenagers entered the water at a jetty.
The boys had stopped off at the lough while cycling in the area.
The Police Service of Northern Ireland (PSNI) said officers were called shortly after 6.25pm to reports of a number of people in difficulty in the water.
The Northern Ireland Ambulance Service (NIAS) said a rapid response paramedic, five emergency crews, a hazardous area response team and an ambulance officer were dispatched.
NIAS also tasked the air ambulance to attend the bank holiday Monday incident.
One of the boys was taken from the water but later pronounced dead in hospital.
The body of the second youth was recovered late on Monday night following extensive searches by Foyle Search and Rescue and police divers.
Another male was taken to hospital for treatment for injuries not believed to be life threatening, while three others have been left shocked, police said.
Local priest, Father Michael Canny, said the boys who died were from the local Indian community in the Waterside area of Derry.
“The families involved are very well known here in the Waterside area. They are part of the Syro-Malabar community who worship here at St Columb’s (church) in Waterside,” he told BBC Radio Ulster.
“Fortuitously, their chaplain was here yesterday evening and he was able to console them and to be with the families right up into all hours of the night.”
Councillor Rachel Ferguson went to the scene.
“The boys were just out for a cycle. They’d gone down and they stopped off at the local jetty,” the Alliance Party representative told Radio Ulster.
“They were both in the water and it seems that one boy has got into trouble and the other boy has gone to help him and unfortunately they were pulled under.
“The other boys flag down a car and some local residents to try and help. They rang the local services – the emergency services – who were in attendance very, very quickly.
“It’s just a tragic accident that happened within the water.”
PSNI’s Inspector Brogan said: “Enquiries are ongoing into this incident but we believe, at this stage, that this was a tragic drowning incident.
“Our thoughts are with the families of those affected.”