A young father-to-be shared a heart-warming message online, telling his son "You'll never have me out of your life" less than two hours before he was stabbed to death.
Glen Osborne (20) died on Wednesday night after being attacked and stabbed once in the upper body in a flats complex in Dublin's north inner city.
The only suspect in the case - a 16-year-old boy who was formerly a close pal of Glen - was arrested shortly after the murder and remained in custody at Mountjoy Garda Station last night.
Senior sources said witnesses described how Glen called his attacker "a rat" during a row between the pair only moments before he was stabbed.
Glen was discovered critically injured at Ballybough House on Poplar Row at around 10pm and was rushed to the nearby Mater Hospital, where he died.
Earlier in the evening, he posted a message on his Facebook page, sharing a picture of an ultrasound scan of his son.
"I just can't wait till you're born to see you to get a father and son bond. I'll be there for you no matter what," he wrote, adding: "You'll never have me out of your life the love I have for you it's just mad what's going on but I'll still stand by you no matter what. A little boy you mean everything to me."
The post was written at 8.11pm. Less than two hours later, Glen, from Taaffes Place, was fatally wounded.
A short time after the incident, detectives arrested the 16-year-old, from the Phibsboro area.
Despite his age, the chief suspect is well-known to gardai for minor drug offences and carrying knives.
He had previously appeared before the children's court.
Gardai have launched a murder investigation but are not looking for anyone else.
They believe a number of other young people were in the area at the time.
"Up until about 10 days ago, the teenager and the victim were very close pals and hung around with each other all the time," a senior source told the Herald.
"There are even photos of them posing together in happier times before they had a big falling-out.
"The grouping that these two lads were involved with got in a dispute with another group of young lads that seems to be indirectly about drugs.
"Gardai are working on the theory that the background to the murder is that it is linked to the falling-out between the two groups, and either the arrested teenager or the victim was accused of being involved with the other group."
Members of the Garda Technical Bureau carried out an examination of the area.
A blue tent was used to cover the scene, which is next to a small football pitch and overlooked by a number of apartments facing onto the Royal Canal.
Searches were also carried out along Luke Kelly Bridge, which is beside Ballybough House, where the arrested teenager was seen discarding a bag.
While nothing of evidential value was found in the bag, senior sources said gardai believe they recovered the knife used in the murder during a search of the Tolka River, but tests need to be completed.
A large garda presence remained in place at and around the scene yesterday.
It is understood Glen was an only child and lived with his mother.
Former Lord Mayor of Dublin and north inner city councillor Christy Burke said his sympathies go out to the family of the victim.
"There's a dark cloud hanging over us as a result of the coronavirus, but that dark cloud has deepened over Ballybough this morning," he said.
"It's a sad day, and a family has lost a son. The feeling in the area is just numb.
"My heart goes out to the family. It's hard to put what happened into words. I know the kid's mother and she is a decent, hard-working community woman.
"All I can do is offer my sincerest sympathies."
Local Independent councillor Nial Ring, who is also a former Lord Mayor, said: "The deceased comes from a very well-known family in the inner city and locals are sad that a young vibrant life has been taken.
"There is also a sense of shock that such an incident took place in the heart of our community.
"The news the alleged perpetrator is under 18 has added to the feeling of helplessness."