Mengmei Lange, who was also known by her middle name Michelle, was born January 29, 1991 in Chengdu, Sichuan Province, China.

Michelle grew up a kind, sensible and respectful girl.

She had a very close relationship with her parents, so it was very hard for Michelle when her father died in an earthquake in 2008.

She received good grades in school and dreamed of moving to Australia.

Her mother, Mei-Jung Lange, supported her through everything and believed that if her daughter got an education in Australia, she would have a bright future waiting for her.

In 2011, Michelle joined the University of Technology in Sydney.

This allowed her to come to Australia and fulfill her long-held dream.

Michelle's aunt, her mother's sister, lived in Australia and offered her a room in her apartment.

She also had a daughter who was two years younger than Michelle.

The following year, in 2012, Michelle's aunt, who was 44, married Derek Barrett, who was 20 years younger than her.

Derek was a temporarily unemployed IT professional and he was only three years older than Michelle.

Since then, Michelle, her aunt, cousin and Derek have all lived together in suburban Campsie, New South Wales.

The first few years were fine, Michelle excelled in her studies, made new friends and found a part-time job in her spare time.

Beginning in 2016, Michelle's aunt often spent time in Wollongong for work, and Michelle, her cousin and Derek still lived in an apartment in Campsie.

In April 2016, Michelle's aunt went on another business trip and was scheduled to return on April 24th.

Three days before that date, Michelle, who was 25 years old at the time, was out with friends.

At about noon, she took a bus from University of Technology Sydney to a downtown shopping mall.

Security cameras captured Michelle shopping on Pitt Street in Sydney's Central Business District around 3pm.

She was alone, and the footage showed she was fine, not bothered by anything.

The vision also showed her later catching a train from St.

James Railway Station to Campsie Railway Station, where she arrived around 4.30pm.

The Campsie train station was the last place Michelle Lange was seen alive, but that day she used her cell phone to communicate with friends and family until late in the evening.

Those who spoke with Michelle that evening did not notice any anxiety or anything unusual in her voice.

On Sunday, April 24th, Derek drove to the train station to meet his wife, who had returned from a business trip.

Aunt Michelle asked Derek about her niece, and he said he hadn't seen her in two days.

Derek was unemployed during that time, sitting late at the computer and waking up late, so he said he and Michelle hadn't seen each other.

He also said that Michelle had been spending a lot of time with her girlfriends and going to nightclubs lately.

Michelle's cousin often stayed overnight at friends' houses, so she didn't see her either for a few days.

The situation was such that no one had seen Michelle since April 22nd and her phone had been turned off.

This was quite unusual since she kept in touch with friends or family members living in China on a daily basis.

It was also strange that Michelle did not log into her social media accounts.

The truth is that these days, if someone who used to be an active user of social media and spent several hours a day on it suddenly stops logging into their accounts, there is a good chance that something bad has happened to them.

Michelle's aunt checked her room, trying to figure out where she might have gone.

The room was in perfect order.

All of Michelle's things were in their places, and it looked as if she had simply vanished into thin air.

The next day, Michelle's aunt and her husband Derek went to the police station and filed a missing persons report.

They also informed the Chinese embassy of Michelle's disappearance.

At the police station, Derek told them about the last time he had seen Michelle, and her aunt said that she had just returned from a business trip yesterday and they had not been able to locate Michelle on their own.

Much to the dismay of everyone who cared about Michelle, her body had already been found by the time the police report was filed.

The day before, at about 10.30am on Sunday, April 24th, several people called the police to report seeing a body floating in the water near Snapper Point, that's about 80 miles from Campsie.

That same day, some Australian news outlets reported the discovery of a woman's body.

The report stated, A woman's body has been found face down inside a blowhole on the New South Wales central coast.

Police said they were treating the death as suspicious and yesterday established a crime scene at Snapper Point in the Munmorah State Recreation Area, located near Mooney Beach between Gosford and Newcastle.

The woman, who has not been identified, is described as of Asian appearance, aged between 20 and 35 and about 170 centimeters tall.

A post-mortem examination will be conducted to pinpoint the cause of death.

A rescue helicopter spokesman said it was not known how long the woman had been there or how she ended up in the water.

Detective Chief Inspector Gary Jubelin of the New South Wales Homicide Unit said, We are creative in the way that we can recapture the area and what's gone on in the area, so we're reviewing CCTV footage, canvassing that type of thing.

I won't reveal what we've uncovered, but we're getting a pretty good understanding of what occurred in that area during that time," he said.

Now that the police had received a report of Michelle's disappearance, they quickly cross-referenced this information with the woman whose body had been found at Snapper Point and whose identity could not yet be determined.

Michelle's relatives were given the sad news that she was the one found dead.

Inspector Jubelin said police had informed members of Ms. Ling's family, living both in Australia and overseas, of the news.

We spoke to Michelle's auntie who she lives with, then I spoke to Michelle's brother by phone who she lives with in China," he said.

It's terrible news to deliver and you can understand how upset they were.

Police have asked anyone who knows anything about Michelle's activities over the weekend to come forward and report it so that detectives can find out as quickly as possible who is responsible for this horrific crime.

When the body was recovered from the water, there were a number of injuries indicating that Michelle had been very violently assaulted.

At the autopsy, the medical examiner counted more than 30 stab wounds on her body.

She fought for her life and tried to fight back against the perpetrator, which resulted in defensive wounds on her arms.

A few days after learning of Michelle's death, her mother flew to Australia to see her daughter's dream place, still unable to comprehend her death.

We even today still cannot accept the fact that she has left us, and we are still in great suffering," Ms. Zhang said.

The time when Meng Mei and I lived happily with each other will never come back, she said.

You can never imagine how painful it is to me.

The saddest thing in life is losing someone you deeply love.

While investigating the case, the detective interviewed Michelle's aunt and her husband, since it was in their apartment that she lived and they knew her best.

Derek said that the last time he saw Michelle was on the evening of Thursday, April 21st, during dinner.

Afterwards, they watched a movie, and then Michelle went to sleep in her room.

On Friday, April 22nd, when he woke up, Michelle was no longer home.

He woke up late, so it was not unusual for her to have already left.

According to him, when he went to bed, Michelle had not yet returned, so he thought she was out somewhere having fun with friends.

The next day, he woke up late again, and Michelle was still missing.

He didn't know if she was coming home, so he texted her, asking where she was and if she was okay, but the text went unread.

Michelle's aunt had nothing to say because she was on a business trip.

Still, some Australian media also report that Michelle's aunt told a detective that she checked Michelle's Facebook correspondence on her laptop and learned that her niece had recently dated an Australian guy and said tellingly, I've seen pictures, and he has golden hair, pale skin and fierce eyes.

Therefore, the police assumed that Michelle had gone on a date with a man she had met online.

However, that version was soon pushed to the back burner.

In fact, investigators already had a suspect involved in Michelle Lange's death.

Derek Barrett was the last person to see her alive.

The police were skeptical of his stories about waking up late and therefore not seeing Michelle.

They called him in for questioning and began asking him questions about his relationship with Michelle, asking him to recall the last time he had seen her, and so forth.

Derek then refused to answer the questions and demanded a lawyer, at which point he was informed that he had been arrested as a suspect.

The fact is that investigators checked his cell phone signal and learned that he had been in the same area where Michelle's body was found on April 24th.

This information contradicted the man's statement in which he claimed he had not visited the Snapper Point area that day.

Police also obtained camera footage that showed a car matching the description of Barrett's car in the early morning hours of April 24th, near Snapper Point.

However, the image was blurry and Barrett began to claim it was not his car.

That claim, too, was denied by police.

Detectives found video footage of Derek Barrett paying for gas and buying drinks at a gas station on his way to Snapper Point.

The image is of good quality and leaves no doubt that it is Barrett.

When told that he was lying about what he was doing on April 24th, he began to claim that he had memory problems and could not remember certain periods of time because he often used illegal substances.

Barrett's cell phone was seized and turned over to specialists for analysis and recovery of previously deleted data.

What was found on the phone left no doubt that Derek Barrett was not only involved in Michelle's death but had an unhealthy interest in her.

His own stepdaughter was also the object of his lust.

A 15-minute video shot in September 2014 shows his wife's daughter, his stepdaughter, taking a shower.

Derek set up a hidden camera in the shared bathroom, hiding it behind toiletries.

In another video, investigators saw Derek enter his stepdaughter's room while she slept, stand next to her bed, and engage in self-satisfaction.

A little time passed and Derek Barrett shifted his interest from his stepdaughter to his niece.

On his phone, experts were able to recover a half-hour video showing Michelle taking a shower.

Another video showed Derek satisfying himself by standing next to Michelle's bed while she slept.

The phone also contained images taken just before Michelle's death.

Now, we already know that Michelle returned home around 5 p.m. on April 21.

Around midnight she sent the last text message from her phone and no one has heard from her or seen her since.

It was after midnight that Derek Barrett began to put his insidious plan into action.

He attacked Michelle, tied her up, and taped her mouth to keep her quiet.

In photos on his phone, investigators saw Michelle bound and naked lying on a bed with terror on her face.

The photos, of which there were 17, showed that Michelle did not yet have the injuries from which she died.

The last picture Derek took was around 8 a.m. on April 22, at which time Michelle was alive.

At about 4 p.m. that same day, Derek's stepdaughter returned home.

The young woman was unaware that her cousin was lying tied up in the next room.

When questioned by investigators about that day, she said she had been home for about three hours before she left again.

She did not hear Michelle call for help.

Experts were unable to determine the exact time of death, so it is not known if Michelle was alive at the time, but it is known for sure that she was still in the apartment.

For the entire three hours she was home, Derek was in the bathroom with the shower on.

The next day, April 23, Derek left the apartment four times to take out trash bags.

This was caught on surveillance cameras.

Supposedly Michelle was already dead by this time and Derek was cleaning the house.

Michelle's aunt, Derek's wife, told investigators that when she returned home from a business trip, it was very clean, but she didn't give it much thought at the time.

At 3.19 a.m. on April 24, Derek drove to Snapper Point.

On the way, he stopped at a gas station where he bought drinks and filled the car with gasoline.

Upon arriving at Snapper Point, he disposed of Michelle's body and took some pictures at about 9 a.m.

An hour and a half later, police received a report from eyewitnesses who saw the body in the water.

Derek visited his parents in the meantime, who did not notice anything out of the ordinary in his behavior, and then returned home to Campsi.

Derek Barrett was indicted on 27 counts, including charges of unlawful imprisonment, secret videotaping, and taking the life of Michelle Lange.

It is worth pointing out in particular that he was not charged with soliciting for lustful purposes.

Like many criminals, Derek began to complain about a difficult childhood, being bullied at school, and the like.

Somehow, some people believe that a difficult childhood can be an excuse for their abusive actions.

The trial began in October 2017.

The psychiatrist who examined Derek concluded that he could be held fully responsible for his actions.

A psychiatrist testified that Barrett told him, I lost everything because of a stupid weekend.

Derek wrote a letter apologizing to his wife and Michelle's family, specifically stating, No words can begin to describe the emotional pain I have caused to you and the family.

I can only imagine what you must be going through from your loss.

Every moment of my life, I wish I could go back in time and take back that day that has caused so much pain.

I let my own problems spill into the family home, and they paid dearly as a result.

All I can do, in some small way, is to commit my life to trying to make up for what I have done in any way possible.

In the mother's translated victim impact statement, Tam May Jong asked the judge to sentence this vicious rapist, malicious torturer, and cold-hearted murderer to life imprisonment.

In April 2016, the death of Mung May had brought great pain to my whole family and I, a single mom trying to support her daughter who was an international student in Sydney, she said.

My healthy mother was in such grief that she too passed away, not long after receiving the news of Mung May's death.

This double tragedy dealt such heavy blows to my family that we are still in irrevocable suffering till date.

Faced with multiple charges, Derek Barrett pleaded guilty.

In December 2017, he was sentenced to 46 years in prison with the possibility of parole after 34 years and 6 months.

Barrett sat with his head down during his sentencing and barely reacted.

He was supposed to be eligible for parole in 2050, but circumstances changed.

Detective Gary Jubelin addressed the media outside court, welcoming the lengthy sentence.

The courts have recognized the seriousness of the offense by the sentence that was handed down on Mr. Barrett, he said.

From an investigative point of view it is satisfying that we've got justice, but there is no joy in a matter like this, it's just an extremely sad case.