Kiesha

Kiesha Weippeart … her body was set alight in a shallow grave. Photo: Supplied

IN THE days after Kiesha Weippeart was reported missing in August 2010, as her step-father Robert Smith pleaded for public assistance to find her, detectives began an undercover operation focused directly on him and another person charged with Kiesha's care.

Within days detectives had set up telephone intercepts, covert surveillance and listening devices at the Seven Hills housing commission flat where the family were staying.

Ten months later, on April 21, 2011, the breakthrough came.

In a secretly recorded conversation with an undercover operative, Smith revealed the true, gruesome circumstances of Kiesha's death and the attempted cover-up that followed.

This scenario and the moment of confession was revealed in court documents tendered in the Supreme Court on Friday, as Smith, 32, was sentenced for manslaughter and accessory to murder.

Smith told the undercover officer of hearing a ''loud bang'' in Kiesha's bedroom and discovering her lying on the floor with a woman standing nearby.

The woman will face trial for murder later this year and cannot be named.

''I saw she was like she was knocked out sort of thing,'' he told the officer.

''So, just trying to, you know, you know wake her up and everything like that … It's just, yeah, like she wasn't waking up or nothing. I was like 'how can this shit happen to me?' ''

In an act which the Crown prosecutor Keith Alder described during Friday's court hearing as ''gross criminal negligence'', Smith did not call an ambulance.

Instead, the court heard that after attempting to revive her, he went to bed and headed to work as usual the next day.

When he returned home that night, Kiesha was dead.

''I was like, mate I am getting out of here, and I am not going back there, you know, and … like you can't do that,'' he told the officer. ''Got to do the right thing and stick by her.''

The documents reveal that Smith then began a calculated and concerted attempt to cover up Kiesha's death.

The dead child's body was placed in a suitcase and left for a week.

Smith and the woman then called a taxi, providing a false address to the driver to hide any connection between their home address and the destination - bushland in the nearby suburb of Shalvey.

''It was like normal you know, 'Pop the boot, buddy,' put the luggage in,'' he is documented as telling the undercover officer.

When they arrived, Smith carried Kiesha's body to a shallow grave, dropped her in, poured petrol over and set her alight.

''I tipped it all on, lit it up with a couple of sticks … and then afterwards threw the bottle in.''

An autopsy later found that Kiesha had suffered a major head injury shortly before she died, and a number of bone injuries that suggested long-term abuse.