CNN — 

As the reality of Liam Payne’s death sets in, his family, friends and former One Direction bandmates are still trying to make sense of the devastating loss while authorities press forward in their investigation into the circumstances surrounding Payne’s final moments and fatal fall.

Payne died Wednesday after falling from the third floor of the CasaSur Palermo Hotel in Buenos Aires, Argentina. He was 31.

His death remains under investigation Friday by local authorities, who are working to determine the nature of Payne’s fall as more details begin to emerge.

The public prosecutor’s office in Argentina said Thursday that “everything indicates that the musician was alone when the fall occurred.” The prosecutor’s office also suspects Payne, who was previously open about his struggle with addiction and his mental health, was potentially “experiencing some kind of episode due to substance abuse” at the time.

A picture released by police in Buenos Aires Wednesday shows a table in Payne’s hotel room with items scattered across it, including unidentified white powder, crumpled tinfoil and a lighter. Some charred marks are also visible on the table.

They also suspect he may not have been fully conscious at the time of his fall. “Due to the position in which the body was found and the injuries from the fall, it is presumed that Payne did not adopt a reflexive posture to protect himself and may have fallen in a state of semi or total unconsciousness,’” the report read.

Marcelo Roma, the prosecutor in charge of the investigation, confirmed the preliminary autopsy report determined Payne’s death was due to multiple serious injuries and “internal and external hemorrhage” as a result of the fall.

Six people believed to have witnessed Payne in the hours before he died spoke with local police in Buenos Aires on Thursday, as part of the investigation into the singer’s death.

Two women, the musician’s manager, and three hotel employees gave testimony to the city police, authorities told CNN on Friday, as investigators work with the Prosecutor’s Office to reconstruct the events. The women who testified were with the British singer in his hotel room but had already left when his death occurred, according to the Prosecutor’s Office.

The results of the toxicological tests to determine if Payne was under the influence of alcohol or other substances at the time his death are still pending.

On Wednesday, Buenos Aires police initially responded to the hotel after a staffer requested urgent police assistance via a 911 call to help with a hotel guest who was “overwhelmed with drugs and alcohol” and whose life they feared was “at risk,” according to the emergency call obtained by CNN’s local affiliate Todo Noticias.

A report later released by the public prosecutor’s office stated that a series of substances were seized from Payne’s room that might “indicate a prior situation of alcohol and drug consumption.”

Whether Payne jumped from the balcony of his room or accidentally fell remains unclear.

Buenos Aires police previously told The Associated Press in a statement that they believe the former, but did not elaborate on how that conclusion was reached and referred CNN to the prosecutor’s office for more information.

Payne’s family said in a statement they’re “heartbroken” by his death, according to the UK’s PA Media news agency.

“Liam will forever live in our hearts and we’ll remember him for his kind, funny and brave soul,” the statement read. “We are supporting each other the best we can as a family and ask for privacy and space at this awful time.”

Harry Styles, Niall Horan, Louis Tomlinson and Zayn Malik – the remaining members of One Direction – honored their friend and former bandmate on Thursday with a group statement and several individual remembrances.

“We’re completely devastated by the news of Liam’s passing,” the band’s joint statement read. “The memories we shared with him will be treasured forever.”

The quartet added, “We will miss him terribly. We love you Liam.”

One Direction formed in 2010, assembled at the time by producer Simon Cowell after he noticed each member’s musical talents when they individually auditioned for the UK version of “The X-Factor.”

Once they became a group, they skyrocketed in popularity and became known for hit songs including “What Makes You Beautiful,” “Best Song Ever,” and “Story of My Life.” Known as 1D by their avid supporters, they became the first band to have its first four albums claim the No. 1 spot on the Billboard 200.

Having sold more than 70 million records worldwide, One Direction remains one of the best-selling boy bands of all time.

In 2015, Malik left the group and one year later, they disbanded after announcing they were going on an “indefinite hiatus.” All five former members went on to pursue solo careers, including Payne, who released his most recent single “Teardrops” in March.

“Liam was an incredible song writer with a great sense of melody, we often spoke of getting back in the studio together to try and recreate the writing chemistry we had built up in the band,” Tomlinson wrote on his Instagram page on Thursday.

Payne, Tomlinson continued, was “the most vital part of One Direction. His experience from a young age, his perfect pitch, his stage presence, his gift for writing. The list goes on. Thank you for shaping us Liam.”

Malik, too, shared the same sentiment when he paid tribute to Payne Thursday.

“When it came to the music Liam, you were the most qualified in every sense,” Malik wrote, directly addressing Payne. “I was always happy to know, no matter what happened on stage we could always rely on you to know which way to steer the ship next.”

Horan said he’s “absolutely devastated about the passing of my amazing friend,” in a statement posted to his Instagram account Friday.

“Liam had an energy for life and a passion for work that was infectious. He was the brightest in every room and always made everyone feel happy and secure,” Horan wrote. “I feel so fortunate that I got to see him recently. I sadly didn’t know that after saying goodbye and hugging him that evening, I would be saying goodbye forever. It’s heartbreaking.”

On Friday, Cowell broke his silence concerning Payne’s death, writing on his verified Instagram, “You never really know how you feel about someone until a moment like this happens” and adding that he is “devastated. Heartbroken. And I feel empty. And I want you to know how much love and respect I have for you. Every tear I have shed is a memory of you.”

Later in his post, Cowell wrote that Payne had come to see him last year. “Not for a meeting. Just to sit and talk. And we reminisced about all of the fun times we had together. And how proud you were to be a Dad. After you left, I was reminded that you were still the sweet, kind boy I had met all of those years ago.”

As news of Payne’s death began to spread around the world, One Direction supporters gathered outside of the Buenos Aires hotel where Payne died. Many played music, lighted candles and shared stories about what the band and Payne meant to them.

“His greatest joy was making other people happy,” Styles wrote in a separate statement posted to his Instagram page Thursday. “It was an honour to be alongside him as he did it.”

CNN’s Sol Amaya and Ana Melgar contributed to this story.