Little did he know, it would cost him his life.

The 24-year-old Darlinghurst resident, who would be 26 today, accepted an invitation from friends to attend the GEOHectic music festival in Lower Portland, more than 30km north of Richmond, on Saturday, August 6, 2016.

But early the following day, Chalaer left a car packed with his friends, his wallet, passport and insulin — to treat his type 1 diabetes — and headed out into the bush.

He was never seen again.

The Disappearance at Dawn

TIEMUZHEN, who was known as Tim to family and friends, was a Chinese student studying hotel management in Sydney before he disappeared.

The ambitious young man travelled the globe to undertake further studies before settling in Sydney’s inner-city eastern suburb in a share house.

The case, which sent shockwaves through the Hawkesbury and Hills Shire, sparked a month- long search by hundreds of volunteers through dense bushland.

Yet all that was found was a pair of shoes and socks placed a short distance from the campsite.

It is understood Tiemuzhen and several friends camped overnight in a car as part of the two-day festival in the Hawkesbury riverside suburb.

In the early hours of Sunday, August 7, 2016, he left the car and his belongings behind, and headed out into the bush.

Several partygoers said they saw him in a blue and red scarf and beanie.

But his friends claim he was never seen again.

LOST IN SYDNEY PODCAST SERIES — EPISODE I

LOST in Sydney is an investigative podcast series produced by NewsLocal. This is the second instalment of some of the most tragic of unsolved cases written to coincide with the start of Missing Persons Week. Click below to read the full extended version of the story of the disappearance of Stephen Lapthorne and Michelle Pope and the lime green van.

READ MORE: Episode One — The Lime Green Van

The Search

TIEMUZHEN’S father said his friends were unaware that he had been missing for several hours before leaving the party without him.

“Tiemuzhen’s friends left the party, they thought that he had made his own way home to Darlinghurst,” Hakki Chalaer said.

“It wasn’t until they contacted Tim’s flatmates that they realised he had not returned, so they drove from the city back to Windsor police station to inform the police.”

But it was Tim’s sister, Esin Chalaer, who was the first person to find out he had been missing.

“I was actually contacted by Tim’s housemates and not the friends he went to the party with,” Esin said.

“I will never forget that day, I had a really restless sleep and then I woke up to the message from his friends to say that he was missing.

“I second guessed the information at first and then they told me he went missing in the bush.”

Esin said she was forced to contact her parents in China, fearing she was “dramatising the situation”.

“When I knew the whole story, I knew they needed to know and I needed to be in Lower Portland,” she said.

“I had a moment where I was about to break down but I held myself together — I was the only family in Australia, they weren’t here, so I knew I had to be strong.”

Ms Chalaer, 28, was the first relative to arrive at the festival site, which she described as

“extremely difficult to find and a wall of green bush”.

“It didn’t have an address. It was in the middle of nowhere, it was a secret,” she said.

“There were so many things running through my head. He wasn’t a nature guy, so it was strange knowing he decided to go there.

“He had diabetes, so there was a very short time period of survival, so I knew we needed to search immediately.”

Ms Chalaer said police did an outstanding job in the search for her brother and said manpower and technology were used to locate any signs of him — and yet no clues were found.

“Police walked shoulder-to-shoulder, they used dogs and even drones to find Tim,” Ms Chalaer said.

“So there is only two real conclusions I can come to at the stage — either Tim is in the bushes and it is incredibly unlucky that we missed him, or he is not.

“I do not think we have done enough to look into option two. What if he isn’t in the bush at all?”

THE PLEA

POLICE and the Chalaer family echoed each others’ pleas for partygoers to come forward and give evidence to investigators. However, only half were willing to be formally interviewed.

Mr Chalaer continues to call for partygoers to contact the police with any information about the music festival and called for searches to continue in the bush.

“We need the coroner to step in and demand people to come forward to answer questions,” Mr Chalaer said.

“The coroner can ask anyone to come forward, and then we might find out what happened to our son.”

Ms Chalaer fears the reason that people refused to come forward to give evidence to police about her brother was because of the amount of illegal substances used at the event.

“A lot of people didn’t want to come forward,” she said.

“Clearly some people are hiding from the truth and don’t want to say that they were using illegal substances.

“Some of the key people involved wouldn’t step forward.”

Esin hit out at Tim’s friends that attended the party for not only leaving without him and failing to contact police in the hours following his disappearance, but also their resistance against supporting the family and detectives with the investigation.

“They knew he had type 1 diabetes and they did not call the police immediately — it’s just such a bad decision,” Esin said.

“He could be somewhere really close by in the bushland, or he could have been the victim of an accident or even foul play.

“We have searched so far and wide at the site, so why was he not found? We have to consider the fact that he may not be in the bush.”

GUITAR PLAYER

THE AFTERMATH

THE Chalaer family has been dealing with the disappearance of Tim in very different ways.

His parents have decided to be outspoken and call for the searches for their son to continue, rallied for an inquest to be held and are proactive on social media.

However, his sister contains her emotions.

Esin fears that if she talks about it too much, it will become too real for her to cope.

“I know I’m not coping very well with what happened, I don’t think I ever will,” she said. “It’s a very difficult to talk about and it’s not something I can just share with anyone.

“It’s not something I even feel comfortable going into a counsellor to talk about.”

Esin pleaded with partygoers to come forward and share their stories, convinced someone knows what happened to her brother.

“I know he’s out there and both my parents and I just really want to find him no matter what happened,” she said.

“We just want closure.”

Tiemuzhen’s family pleaded for the NSW Coroner Court to conduct an inquest into his disappearance for several months.

His father revealed an inquest would be held by the NSW Deputy state Coroner from September 13, to identify exactly what happened to his son.

Lost in Sydney: The Series

Episode II — The Party in the Bush

Produced and presented by Jake McCallum — jake.mccallum@news.com.au

Audio and editorial production by Laura Sullivan and David Wood

Artwork by Daniel Murphy

Editing by Joanne Vella

LOST IN SYDNEY PODCAST SERIES — EPISODE III

ON BOXING Day 1982, a 10-year-old indigenous boy named Bradford Pholi jumped the back fence of his Dundas Valley home to scurry off to Eastwood station — he is on a mission to borrow money for his mother — minutes later his brother goes after him, but is never seen again.

The disappearance of the young boy with pearly white teeth, dark brown eyes and brown hair that frames his face, resulted in the early death of his mother and a spiralling battle with substance abuse for his siblings.

Bradford’s story, The Boy and the Red Rattler, is the third instalment of the Lost in Sydney podcast series, and is to be released on Monday, August 20.