Teenager Azzam Raguragui may have been killed because of a row between two groups of youths over a stolen bike, garda sources said yesterday.
Azzam (18), who was stabbed to death last Friday, is not suspected of stealing the bike that allegedly led to a confrontation in a South Dublin park.
It is believed he might not even have been the intended target of the stabbing in Finsbury Park, Dundrum.
"This is a very sensitive and complex investigation involving witnesses who are juvenile males," a source said last night.
"No arrests have yet been made."
The bike link emerged yesterday as the Herald learned that a 15-year-old boy was stabbed not far from the scene of Azzam's murder, only 10 minutes later.
The stabbing happened at a bus stop on Nutgrove Avenue, Rathfarnham, less than 2km from the park, at 8.20pm.
Gardai could not confirm if the stabbings were linked.
It is understood the teenager attacked in Rathfarnham suffered a thigh injury and was taken to Crumlin Hospital.
"A male youth sustained an apparent stab wound during an incident on Nutgrove Avenue at approximately 8.20pm on May 10," a garda spokesperson said yesterday.
"It's understood he was assaulted during an incident involving a number of youths. The investigation is ongoing, and no arrests have been made."
A resident from Rathfarnham, who did not want to be named, told the Herald that locals rushed to the assistance of the injured teenager.
"The young man was bleeding very heavily, and the bus stop was covered in blood," he said.
"Gardai sealed off the area and were making door-to-door inquiries throughout the weekend."
Gardai are appealing for witnesses or anyone with information to contact them on 01 6666500 or the Garda Confidential Line, 1800 666 111.
Azzam, who has been described as respectful and cheerful, had been due to attend evening prayers in Clonskeagh Mosque last Friday.
Detectives leading the murder investigation quickly ruled out a racial motive for the killing.
Officers have already spoken to a teenager who is the chief suspect.
The youth, who is from South Dublin, has claimed he acted in self-defence when he fatally stabbed Azzam.
A source said the boy had presented himself to gardai on Saturday, accompanied by a legal adviser and carrying a prepared statement.
Officers have spoken to a number of people in relation to Azzam's murder, but are continuing to identify everyone who was present in the park on Friday.
Gardai have been called out to several incidents in the area in recent weeks and responded to reports of a brawl involving a number of youths last Saturday week.
Known to his friends as Azzy, the dead youth was well-known in the Dundrum area.
Earlier this week, his devastated parents, Abderrahmane Raguragui and Hajiba Elouaddaf, thanked the public for their support and said they are hopeful that those responsible for their son's murder will face justice.
"The past few days have been very difficult and challenging for our family," they said in a statement.
"An Garda Siochana is leading the investigation to uncover the truth behind our son Azzam Raguragui's murder and we are resting our faith in the Irish justice system to hold the perpetrator(s) to account.
"We are grateful for the community support we have received. At this critical time we would like to request some space and privacy to allow us to grieve as a family."
Clonskeagh Mosque will hold a gathering on Saturday evening in memory of Azzam.