Aaron's mother disappeared when he was three. He always insisted he knew what happened to her.

On Christmas morning in 1992, Bonnie Haim opened presents with her husband Michael and their three-year-old son Aaron.

Just two weeks later, she was gone.

After Bonnie Haim failed to show up at work on that January morning, police began searching for the missing young mother.

Roughly five miles away from her Jackonsville, Florida home, the 23-year-old’s purse was found buried in a motel dumpster with her credit cards and cash intact. Her car was parked just miles away at the Jacksonville airport.

From the very beginning, Bonnie’s husband Michael Haim was considered a primary suspect in her disappearance.

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Speaking to police, Michael claimed that his wife had drove off following an argument. He said that he had no idea where she was.

But the couple’s son Aaron had a different story.

In the weeks following his mother’s disappearance, three-year-old Aaron Fraser continually told investigators that “Daddy hurt Mummy”.

According to an arrest affidavit, the toddler also stated “Daddy shot Mummy” and “My daddy could not wake her up”.

But the youngster’s claims simply weren’t enough for investigators.

Although police searched the family’s home, a lack of physical evidence meant police were unable to arrest their prime suspect – Michael Haim.

In the years that followed Bonnie’s disappearance, Aaron was removed from his father’s custody and adopted out to another family.

But even as he grew older, Aaron remained convinced that he had witnessed his father murder his mother.

In 2005, Aaron and his adoptive mother Jeanie filed a wrongful death suit against Aaron's biological father.

After winning the case, Aaron acquired the rights to the house where he grew up.

Years later, in 2014, Aaron and his brother-in-law began to renovate his childhood home.

It was then that Aaron made a grim discovery.

While removing a concrete slab in the backyard of the family home, Aaron's shovel struck something hard.

Initially, the then-29-year-old thought he had found a coconut.

Instead, he had found his mother's skull.

“It looked like a coconut shell. I had it in my hand. We looked back in the hole and saw teeth,” he told police.

“At that point in time, you could actually see the top of the eye socket. And it was like this part of the head, the top half of the head. I set it back in the hole.”

Following forensic testing, it was found that the remains did in fact belong to Bonnie Haim. A bullet casing was also discovered nearby which matched a rifle which Michael had once owned.

Now, more than 25 years on from the disappearance of his mother, Aaron Fraser will serve as a key witness in Michael Haim's murder trial, which began on Monday, April 8.

Amid the beginning of the trial, charging documents revealed that Bonnie Haim was planning on leaving her husband with Aaron shortly before she was killed.

In the weeks before she vanished, Bonnie had been giving money to a friend to keep safe for her. She had also put a deposit on an apartment, which she planned to move to while her  husband was on a business trip.

In recent years, a Facebook page with the name Bonnie Pasciuto Haim has been updating people on the progress of the case.

Last month, Bonnie's sister Liz Mahoney Peak wrote: “Next month is going to hurt. It is going to rip off bandages and expose us to things we had long ago pushed to the back of our memories. But sometimes we have to rip off bandages to really begin to heal."

Michael Haim has pleaded not guilty to second-degree murder. He is currently free on bail while the trial commences.