Nearly eight years ago, in December 2010, Keli Lane was convicted of murdering her two-day-old daughter, Tegan Lee Lane.

The child, who was Keli’s fourth pregnancy in just five years, has never been found.

Now, 22 years on from the disappearance of newborn Tegan, Keli is determined to prove her innocence.

Following multiple unsuccessful legal appeals against her 18-year jail sentence, the 43-year-old has reached out to award-winning Australian journalist Caro Meldrum-Hanna, to investigate her story.

“I was sitting in my office and the daily mail delivery arrived… there was this blue biro, I’ll never forget, this blue biro hand written envelope. I tore it open and there was this perfectly written letter – there wasn’t a mistake in it,” Caro told Mamamia.

“It was essentially saying I have been wrongly convicted of murdering my baby, I need to prove my innocence,” she continued.

From there, working alongside investigative journalist Elise Worthington, Caro delved into one of Australia’s most notorious crimes.

The first episode of EXPOSED: The Case of Keli Lane will air on Tuesday evening on the ABC.

Between 1992 and 1999, Keli Lane fell pregnant five times.

An elite water polo player under the guide of her manager, her mother Sandra, Keli managed to conceal all five of her pregnancies from her parents, her teammates, her friends and family.

“From Keli Lane’s point of view, she thought [concealing the pregnancies] wasn’t hard at all. It was actually sort of remarkably easy,” Caro explained.

“She was wearing baggy clothes, and from all accounts, she did carry her pregnancy differently than most of us visualise a pregnant body,” she added.

“She was an elite athlete… physically and psychologically, she was able to compartmentalise and deal with pain.”

Falling pregnant twice at both 17 and 18 years old, Keli terminated her first two pregnancies in 1992 and 1994.

She hid both pregnancies and the subsequent abortions from her parents and friends.

“She was a prolific liar when she was younger, she told so many lies and wove a web of deception to cover her tracks to prevent anyone in her life finding out about these pregnancies,” Caro said.

“There was that fear of disappointing her parents and shattering that image,

“There was was no room, it seemed, for mistake. You were a winner, Keli Lane was a winner, and that was her role in the family.

“She was a champion. And what she did reflected back on her family, so in her mind, falling pregnant at a young age, particularly out of wedlock too, that was a really bad thing in her life.”

The pregnancy terminations, and in particular, the second abortion which occurred 20 weeks into the pregnancy, took a significant toll on Keli.

“She says that after the termination that she had, she couldn’t do that again. She didn’t want to do that again,” Caro said.

But in the following year, in 1995, she fell pregnant once again.

Her third pregnancy and the first child she would give birth to was a baby girl born in 1995.

Her daughter was soon adopted out.

“In her mind, she thought she was making the best, rational decision that she could make for the baby by giving it up for adoption,” Caro explained.

But it was with her next child, Tegan, that would see Keli take a radically different path.

Tegan Lee Lane was born on September 12, 1996 at Western Sydney’s Auburn Hospital.

Two days after giving birth, the newborn girl disappeared without a trace.

On the same day, Keli attended an afternoon wedding, where she was seen dancing, drinking and acting just like her normal self.

There was no sign of Tegan.

For three years after her birth, no one noticed Tegan was missing. After all, hardly anyone knew Keli’s daughter even existed.

But when Keli gave birth to another child, a son in 1999, red flags were raised when she attempted to adopt out her third secret child.

During the process to adopt out her son, a social worker discovered Tegan’s hospital records.

Although Keli initially lied, denying the existence of any children before her third secret child, she soon claimed that Tegan lived with a family in Perth, leading social workers to alert local police of the situation.

What followed was a lengthy police investigation into Tegan’s sudden disappearance.

Ever since the investigation began, Keli has maintained that she gave Tegan to the child’s father, a man called Andrew Morris or Norris, to raise her. But to this day, police have been unable to track down Andrew or Tegan.

Years after the investigation began, a coronial inquest was held in 2006 before a murder trial began in 2010.

During the entirely circumstantial case, the prosecution maintained that Keli’s motive was clear, saying she wanted to increase her chances of representing Australia in water polo at the Sydney 2000 Olympic Games.

In late 2010, she was found guilty of murdering Tegan, with the Crown maintaining that Keli’s lies were indicative of her guilt.

When Keli reached out to Caro to investigate her case, Keli’s history of spinning lies was a major challenge Caro and Elise had to face.

“She never said a word [to the media]. And now here she was ready to break her silence,” Caro told Mamamia.

“What do you do, and how do you communicate with someone when the person at the centre of it has been found to be a serial liar. How do you know when they’re telling the truth?

“The best I could do was ask her, ‘you have been accused of telling many, many lies over a very long time, are you going to be honest with me?’ And she said she would be.”

Throughout the upcoming documentary series, EXPOSED: The Case of Keli Lane, Caro and Elise also interviewed key people in Keli’s life, including childhood friends and her parents, Sandra and Robert Lane.

Besides an appearance on 60 Minutes back in 2016, Sandra and Robert have stayed away from the media for many years.

“Sandy and Rob have a justified distrust and dislike of the media,” Caro explained, adding that in the thick of Keli’s case, the couple had journalists walking into their house uninvited.

“It was a long process for them to agree to being interviewed,” she added.

But despite their justified distrust of the media, Sandra and Robert invited the cameras into their home.

“I can’t remember a time, maybe a couple of stories I’ve worked on, that matched the level of intensity and the heaviness in the room. The room felt so heavy. It was hard to describe. It was so raw. They were physically shaking in the chair,” Caro described.

“The only reason they’re talking about this is because they believe their daughter is innocent. And that she shouldn’t be in jail. [They believe] there’s no way she could have harmed a baby.”

Caro also speaks to Keli herself throughout the series, as Keli rings her from prison.

For more on this fascinating story, tune in:

EXPOSED: The Case of Keli Lane will air on three Tuesday nights, beginning at 8:30pm on Tuesday September 25 on ABC and iview.