POLICE still don't know exactly what led to the deaths of two people celebrating Australia Day at a remote Queensland property.
Kristy Cini, 23, and Zack Jenkins, 15, were at a rural property in Julatten, north of Cairns, on January 26 when they were both found unresponsive in the water.
Police have centred their investigation on a homemade waterslide at the property that partygoers could slide down before landing in a dam.
Both Kristy and Zack are believed to have used the waterslide, at least 40m in length, before their deaths.
Friends of Kristy's rushed into the water after they noticed her body go limp on the slide right before she landed in the water.
While searching for Kristy, they found Zack's body instead, who had been missing for around 20 minutes.
Emergency services rushed to the property on Mossman-Mount Molloy Rd just after 4pm on January 26.
Upon arriving, officers were told Zack had been found dead in the water and Kirsty was still missing.
An emergency services worker found Kirsty in the water a short time later and despite "extensive efforts" to revive her, she died at the scene.
Acting Inspector Rob Campbell spoke to reporters on the weekend and said it was "a tragic consequence".
"We're looking at it as a very tragic event that's occurred on this day. There were a number of people around that have been coming around for the same amount of years to celebrate Australia Day but there has been this really tragic consequence," he said.
Insp Campbell said the slide had been in place for a number of years and families who went to the private party had been using it for some time.
"The slide is constructed of rubber conveyor belt matting … it's been in place for some four years and has been used at parties across different times by partygoers to slide into the dam," he said.
Speaking to Sunrise, Queensland Police Service spokesman Duane Amos said it had been a "typical" Australia Day event.
"It's a typical Australia Day event where everyone is enjoying themselves. Unfortunately, there is alcohol that's mixed with water and we have the tragic deaths of a 23-year-old and 15-year-old," he said.
Tributes have poured in on social media for the young pair.
Sharing a video on Facebook, Aiden Jay wrote "Zack Jenkins, rest easy lil soldier you'll be dearly missed by all".
Kirsty's brother Adam took to Instagram over the weekend to express his heartbreak and said he was "so lost now".
"Today is the worst day of my life, to find out that I will never see my beautiful baby sister again. I have experienced so much pain in my life but nothing knocks me down like this, I am so lost now.
"RIP Kirsty Cini I'll love you always. Friends and family I will try to keep you posted on when Kirsty's funeral is."
Rebecca Chessells also paid tribute to the Brisbane cheerleader.
"I cannot believe this I am so shocked, she was such a beautiful girl. I cannot imagine how her family is feeling. R. I. P kirsty such a beautiful soul taken way too soon," she wrote.