An 18-year-old male has been arrested on suspicion of murder following the death of a teenager in Londonderry.
Jordan McConomy (19), a former St Brigid's High School student from the Rossnagalliagh area of Derry, was seriously injured in a fight.
The fracas happened in the William Street area, near the Bogside, shortly after 2am yesterday.
He was rushed to Altnagelvin Hospital by ambulance but died of his injuries later.
Police said the 18-year-old had been arrested on suspicion of murder following Mr McConomy's death.
He was last night in custody at Strand Road PSNI Station.
Officers received a report of an assault at around 2.15am yesterday and attended the scene with paramedics from the Ambulance Service.
Police said they believed the victim was involved in an altercation with another male and was seriously injured during an assault before he died.
Foyle SDLP MLA Mark H Durkan, who has spoken to those close to the victim, said they had been left shocked by the loss of a young man described as a gentleman.
"They are devastated, as one could imagine," he said.
"This is awful news for anyone to wake up to.
"It's every family's worst nightmare and our thoughts and prayers are with the victim's family and anyone affected by this tragedy.
"People are shocked and disgusted and most of all saddened by the fact that a young man could be out socialising and not come home.
"It really doesn't bear thinking about.
"As a father, it's every parent's worst nightmare, seeing their son going out for the night and just not coming home."
Foyle Sinn Fein MP Elisha McCallion also expressed her condolences.
"The city woke up this morning to the sad news that a young man lost his life in an incident in the city centre last night," she said.
"My thoughts at this time are with the family and friends of this young man, who will no doubt be devastated at this tragic news.
"There is a great sense of shock and sadness in the community following this death.
"I would call on anyone with information on what happened to bring it forward to the PSNI."
Friends yesterday took to social media to pay tribute to the popular teen.
"This place is one cruel place, rest in peace Jordan," wrote one.
"You'll be missed so much. Look over all of us at this hard time. God only takes the best. Love you bro. Gone but not forgotten."
Another friend wrote: "Mad to be writing this Jordan lad. Never did anyone expect news like this. Not nice at all man. Was only chatting to you last week about the cars and how much you loved your wee motor and that. Rest in peace Jordy and fly high lad".
Another wrote: "Can't believe it. Full life ahead of you. One of the nicest lads I ever met. Sleep tight kid."
Foyle DUP MLA Gary Middleton also expressed his shock.
"Londonderry has been plunged into sadness at this very tragic news. I want to pass on my sympathies to the family and friends of this young man," he said.
"I understand that the 19-year-old lost his life due to an altercation last night.
"It serves as an important reminder to everyone, to be mindful of their actions and the ramifications they can bring."
Detective Chief Inspector Geoff Boyce appealed for witnesses to contact police.
He said: "We know that many people were socialising in William Street early this morning and we would like to hear from members of the public who witnessed an altercation in the area between approximately 1.45am and a 2.15am to get in touch with detectives at Strand Road on telephone number 101, quoting reference number 228 of 24/9/17.
"Police would particularly like to hear from motorists who were either parked on or travelling along William Street during these times and who had a dash cam fitted to their vehicle.
"Alternatively, information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111."