Finbar Sullivan, 21, died after he was attacked with a knife at the view point on Tuesday evening (April 7).
Police have been extensively investigating since the incident.
Yesterday (April 10) officers arrested a 27-year-old man on suspicion of murder, reports our sister-site London Now.
A 25-year-old man was also arrested on suspicion of assisting an offender.
The pair remain in police custody.
Officers were called to the scene at 6.41pm and Finbar died at the scene.
Forensics at Primrose Hill (Image: Joseph Reaidi / NQ)
Another man, believed to be in his 20s, was found nearby on Regent’s Park Road and he was taken to hospital with stab wounds.
His injuries have since been confirmed as non-life-threatening and non-life-changing.
Detective Inspector Andy Griffin, who is leading the investigation, said: “My thoughts remain with Finbar’s family who continue to receive support from specialist officers at this unimaginably difficult time.
“Although we have made two arrests, my officers continue to work around the clock to trace everyone involved.
“I’d like to thank the public who have come forward with information so far.
“If you are yet to speak to us, or share footage from Tuesday relating to this incident, please do not hesitate to get in touch.
“Anything you submit could have a huge impact on our investigation.”
The Metropolitan Police has also said that residents can expect to see an increased police presence in the surrounding area.
Anyone with information is asked to contact police on 101, quoting reference 6448/07Apr.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.


