A policeman at his side, Donovan Moodley entered the family lounge and sank to his knees before his parents, Stephen and Mary, who were sitting side by side on the couch.

"I committed a murder. I killed Leigh Matthews."

His father was dumbstruck. His mother said: "I have prayed every night for the Matthews family."

She looked at her son and asked: "Why?"

He did not answer.

Senior Superintendent Piet Byleveld, 54, had arrested Moodley 39 days after being appointed to lead the investigation into the kidnapping and murder of Matthews, the Bond University student snatched from campus the day after she turned 21.

Byleveld's 121-page statement was never presented to court as Moodley pleaded guilty.

The document describes how he built an overwhelming case against Moodley.

With no meaningful leads, Byleveld began his investigation at the original starting point: Bond University. He found a student who had seen Leigh walking alone towards her car, and suspected she had been kidnapped from the parking area.

Hundreds of interviews followed as he went on to talk to her relatives, friends, acquaintances and university colleagues.

Even though many had already made statements, Byleveld re-interviewed them, convinced that vital clues may have been overlooked.

He visited the spot where her body had been found.

He established where calls had been made from Leigh's phone on the day of the kidnapping.

One vital new clue emerged. Rob Matthews had misunderstood the instructions for the drop-off of the ransom money and had driven through the Grasmere toll plaza. This had prompted the kidnapper to shout at him, revealing his Indian accent.

Byleveld interviewed Eliot Makhubela, the grass cutter who had found Leigh's naked body.

Makhubela said he had been cutting grass in the same area the previous day and was adamant the body had not been there.

Tracking the cellphone calls, Byleveld established that Leigh had been near Bond until 10.22am. Later the phone was used near Walkerville, later still in Johannesburg's southern suburbs and at 8.36pm in the Walkerville area for the last time.

Forensic experts found Leigh had been shot four times; had not been sexually assaulted; her toes and soles were reddened by freezer burn; two hollow point bullets were retrieved from her body; she had died more than a week before she was found.

Byleveld now knew her cellphone had been used in Walkerville and the kidnapper was probably an Indian male.

Byleveld approached the Crime Intelligence Unit who scrolled through reams of records and came up with a fit: a cellphone on the Vodacom network belonging to Donovan Samuel Moodley.

Byleveld contacted staff at the Florida police station's Intelligence Unit and asked them to track down all available information on Moodley.

They came up with his ID number, home address, phone numbers, the fact he owned a gold Toyota Tazz and a yellow Ducati motorbike, and he had a licence for a 9mm Taurus Parabellum pistol. He had a savings account and credit card with Nedbank.

A list of student names from Bond threw up a Donovan Moodley, whose details matched those of the Donovan Moodley they already had.

Moodley had left the university in May, but had studied some of the same subjects as Leigh and she could have known him.

Nedbank provided statements of all Moodley's accounts. Cash deposits totalling R39 000 had been made into his accounts within 18 days of the kidnapping.

Two credit card payments had been made to the Formula 1 Hotel in Bramley, one to Ducati and another of R2 969.10 had been made to Stern's jewellers in Eastgate.

The Ducati dealership in Bryanston told Byleveld that Moodley had paid R13 000 on July 15 for a repair to his bike. He said he could not pay the total repair bill for R38 899 because "a deal went wrong" and "I did not make as much money as I expected".

Vodacom provided all records and information relating to Donovan Moodley's phone for the period June 1 to September 7.

Moodley had made a reservation at the Bramley Formula 1 for seven days from July 6 to 13. He had checked in on Tuesday July 6 and left the hotel on July 10.

On Friday October 1 Byleveld told his team he had identified his man. At 5am on the Monday they staked out the Moodleys' home in Brackenhurst.

After some hours the electric gate slid open and a young Indian man drove out. They followed the car to a nearby intersection where Byleveld switched on his siren and flashing blue light and pulled Moodley over.

Service pistol in hand Byleveld approached the driver, who remained seated. Byleveld reached into the car and took the keys out of the ignition. He asked the man if he was Donovan Moodley.

"Yes. What's wrong?"

Byleveld said formally that he was arresting Moodley for the murder of Leigh Matthews. Moodley responded: "What took you so long? I was expecting you."

Moodley was warned of his rights and grew silent. Byleveld cuffed Moodley's hands behind his back and placed him in leg irons.

He searched Moodley's car and found a leather holster in the glove compartment and a cellphone on the passenger seat.

Moodley was taken to Byleveld's office at the Serious and Violent Crime Unit and uncuffed. Moodley suddenly blurted out: "I'll tell you everything."

Byleveld asked Moodley to point out certain scenes, which he agreed to do.

Moodley took police to a place where he claimed he had burnt Leigh's clothes. Items retrieved including the remains of a cellphone, part of a burnt watch, the wire from an under-wired bra and two keys that fitted Leigh's car.

At Moodley's house, Moodley handed him his firearm, Leigh's ring and a computer disc on which he had saved letters to his parents and girlfriend. In these letters he apologised for what he had done and claimed he was going to jail for 30 years.

He was taken into the lounge where he spoke briefly to his parents before being taken to the Sandton police cells.

Moodley's gun was found to be that used to shoot Leigh.

In a new search of Leigh's car, police found a Lotto ticket with a fingerprint on it and a shoe print on a piece of paper.

Moodley's fingerprints matched the print on the Lotto ticket and a print found on a piece of tape picked up at the scene where Leigh's body was found.

Two blonde hairs, identified as Leigh's, were found on the back seat of Moodley's car.