Justin Bieber leaves his tribute to Liam Payne, following his death
The Wolverhampton born singer died in Buenos Aires on Wednesday.
Justin Bieber has told Liam Payne to "rest easy" as officials continue to look into the circumstances surrounding the One Direction star's death.
Payne's father has travelled to Argentina to arrange the repatriation of his body after the 31-year-old died falling from the third-floor balcony of a hotel in Buenos Aires on Wednesday.
A preliminary toxicology report has suggested the singer had cocaine in his system, an Argentine official told the Associated Press.
Canadian pop star Bieber, 30, reposted a video to his Instagram Story of fans paying tribute to the late singer by laying flowers, balloons and cards, adding "rest easy Liam" and a broken heart emoji.
A voiceover on the clip said: "Just remember, you are allowed to grieve as a fan. You are allowed to love someone you've never met. You are allowed to admire someone for their art. You are allowed, to cry, to break, to feel like a part of you is gone."
The singers both rose to fame in the 2010s, with Bieber's music battling One Direction in the charts at times.
They have spoken about each other in the media over the years, with Payne revealing in an interview with Rollacoaster magazine in 2017 that he had told Bieber to reach out to him if he ever needed support.
Payne told the magazine: "He's a great guy - inside there's a really good heart. I said, 'Look, the difference between me and you is I had four different boys going through the same thing to look to.' He didn't have that.
"I said to him, 'Take my number and any time you want a chat, let me know as I'm here and I understand exactly what you're going through and I understand your world.' He needs somebody like that and in that position."
The final toxicology results are not expected to be made public for some weeks but the initial report suggested evidence of exposure to cocaine, an official told the Associated Press, but stressed the initial results do not offer an accurate reading of how much was circulating in his blood when he died.
Payne died of multiple traumas and "internal and external haemorrhage", a post-mortem examination report said.
Argentina's National Criminal and Correctional Prosecutor's Office No 16 said it was investigating the incident as an "inconclusive death".
It said five witnesses were questioned in order to reconstruct what happened at the CasaSur Hotel in the Palermo area of Buenos Aires.
Reports say staff at the hotel made two calls to emergency services, with audio revealing a staff member had asked for assistance for a guest who was "intoxicated by drugs and alcohol".
Police officers and the emergency services found Payne dead at the scene and his body was transferred to the judicial morgue.
The prosecutor's office indicated the musician was alone when the fall occurred and said he appeared to be "going through some kind of outbreak due to substance abuse".
Forensic experts said no injuries were observed that would suggest the intervention of third parties, although "the investigation is also aimed at determining the possible intervention of third parties in the events prior to his death".
Police in the Argentine capital previously said the music star's hotel room had been "in complete disarray" with "various items broken".
They added that a whiskey bottle, lighter and mobile phone had been retrieved from the internal hotel courtyard where Payne's body was found.
Tributes have flooded in for Payne since the news of his death, including from his former partner Cheryl, his One Direction bandmates, his girlfriend Kate Cassidy, and music mogul Simon Cowell.
Payne's fellow bandmates - Niall Horan, Louis Tomlinson, Zayn Malik and Harry Styles - paid emotional tributes to him and a joint statement from the band said they were "completely devastated" and will miss the singer "terribly", adding the "memories we shared with him will be treasured forever".
Thousands of fans of the singer gathered to remember him at memorial events in the UK and many other parts of the world over the weekend.