47

Detective Constable Mark Travers was originally tasked with the massive job of reviewing all the files of the Allen Redston investigation and collating crime scene material. In 2006 Acting Superintendent Chris Sheehan took over as case officer on the file, in turn passing that baton to Detective Sergeant Tony Crocker in late 2008. Early in January, the three of us talk via conference call. 'Look, we need to be careful here,' Sheehan says. 'We haven't eliminated Percy from the inquiry. But if we eventually charge someone with Allen's murder, which of course we hope is the case, then any decent defence lawyer will jump on it and raise Percy as his potential killer.'

'In other words,' I say, 'you can't rule Percy out, but equally you can't rule him in?'

'That's right. There are reasons for that. The key issue is that we can't place Percy in Canberra on that date but we also can't definitely say he wasn't there. He was then living with his parents at Khancoban, four hours south of Canberra, and while there is some anecdotal rumour about him visiting an aunt at Curtin, there is no proof. It was a school day and four hours is not a huge distance but how did he get there if he was on his own? Did he travel with his parents on one of their shorter trips? As far as we know he did not have a licence. Allen suffered no sexual assault and certainly not the genital mutilation of Percy's one known victim. His killer did not use a knife and the location where his body was found was not widely known. This all speaks to a degree of local knowledge of that area. It appears likely that the offender knew that materials to bind a child would be found there and probably went there for that purpose. He also knew that he would have a degree of privacy. We have a number of suspects who were all spoken to during the initial inquiries. And it is highly likely that the person responsible is one of those people.'

Sheehan proudly defends the thoroughness of the original investigation. 'Every hotel, motel and caravan park's records were checked for people who had come from out of town. They spoke to almost every boy in surrounding areas. They did a lot.'

'So you can't fault that investigation?'

'Look,' he chuckles, 'police are by nature competitive. I've yet to meet a detective who doesn't think they can do a better job than the next one. But apart from the advances in technology that we have today, the investigation under the now defunct ACT Police was sound. What we battle, as in any cold case, is time: the age of witnesses and sharpness of their recollections. That is a major issue in any cold case.'

'In the Simon Brook murder, evidentiary material was thrown away,' I tell Sheehan. He knows this, obviously; these are details that have been aired at meetings or over a few beers with other jurisdictional officers during Operation Heats, which Sheehan describes as a 'co-ordinated, holistic approach to multi-jurisdictional cases'. 'How has the crime scene evidence been preserved in this case?'

'In pristine condition. The area was secured and the exhibits have been kept safe with all correct forensic procedures followed since the murder. Some exhibits got wet at the crime scene before Allen was found and the area was secured, but by no means all the exhibits.' At least, I think, Allen's family can rest a little in the knowledge that if there is any DNA to be compared from the crime scene, it may still be available from those exhibits. The Brook family can take no such comfort.

Derek Percy, a cleanskin to police in 1966, does not feature at all in any running sheets into the original investigation. 'Police didn't know he existed,' Sheehan says. 'Why would they? He didn't come to police attention until the Tuohy matter. They focused, correctly, on the evidence and any possible suspects they had at the time.'

While Percy's sexual penchant for children is now well known, ACT police believed the strongest links to his possible involvement in the Redston case were the tie found at the scene and the fact that the offender rode a bike. Derek's bike, a distinctive maroon colour, did not match the one witnesses saw, which was red and white with a carrier on the back. And why would he have had it in Canberra if he was only visiting? The tenuous link that police thought may have existed between the tie found at Redston's crime scene and the one Percy wore to school at Mount Beauty, believed to have been made by his mother on her home knitting machine, was put under the forensic microscope in 2004 by the Australian Federal Police's Forensics Criminalistic team. 'The tie was found to be made of green and yellow two-ply wool, woven, not knitted,' Sergeant Crocker says. 'The uniformity was even and the conclusion reached that a knitting machine did not manufacture that tie. It was not homemade. And we also have the situation where we have found nothing to directly implicate Percy in this death. He has also made no admissions.'

In 2004, Professor David Barclay, the former Head of Physical Evidence for the UK National Crime and Operations Faculty, now at the University of Hull, was invited to Canberra to lecture to Australian Federal Police staff about forensic advances in investigations. Barclay was well acquainted with unsolved Australian crimes: in 2004 he was part of an independent review team on the so-called Claremont serial killings that had assisted Western Australian police in assessing the likely killer of at least three beautiful young girls who stepped out from nightclubs into the warm Perth night and met their terrible fate. In an interview with Barclay he once told me his job was to look at the lead-up to death, which gives opportunity to recover evidence. 'Everything is a sequence of events which we piece together,' he said. 'Was a victim held by her ponytail? Then the scrunchie that tied her hair may reveal low-copy DNA. Was she knocked to the ground or did she fall? The scratches on her knees reveal she was knocked down.'

In 2006, the AFP turned to Barclay, seeking his expertise on the Redston case, a review which a computer randomly code-named Operation Kobold. While the AFP will not reveal Barclay's findings, their answers to questions regarding other suspects and the drivers that consume Percy – coprophilia, sexual sadism and lust, not seen in Redston's murder – are strong indicators that Percy does not head their list as being responsible for the little boy's death. But he remains a suspect, Crocker confirms, until someone else is successfully prosecuted.

Police had hoped that low-copy DNA, used for testing against a known suspect might, despite the damp and wet conditions in which his body lay, have been found on some of the elaborate bindings the killer used to tie Redston. But there was to be no magical scientific bullet to wrap up this case. 'A lot of reliance was placed on that low-count DNA,' Crocker admits. 'But by April 2007, the results came back that there was no positive response to those tests. The water had destroyed any DNA.'

Allen's father, Brian, is a gravelly-voiced, down-to-earth bloke whom investigating officers protect from the prying press. On a cold winter's day, I locate his number and call him. It is not my style to skirt contacting families; as primary sources, they often have insights that other people do not and just as often they are grateful for the opportunity to talk. If they don't wish to, they quickly tell you.

Another sound reason for making contact is to check facts. 'A writer who wrote a book about my daughter's murder claimed I was dead!' an indignant Elizabeth Schmidt told me the day we met. 'He simply hadn't bothered to contact me. In his next book, I was resurrected with no explanation. It caused our family a lot of unnecessary grief.' But that initial cold contact is still the part of research that I loathe most, finding the right words to say to bridge a distance between strangers without being disingenuous and trite, to break the initial uncomfortable silence. And so it is today.

Brian Redston is unfailingly polite, quiet and decent in an old-fashioned way, but there is tiredness in his voice as he describes his son and it is painfully obvious his sorrow is still horribly raw. 'He was a good outgoing kid, with a good sense of humour.' There is an elongated pause. 'He enjoyed life.' I catch myself before I blurt out what short life he had but I am thinking of the void created by violent, sudden loss, and of what Donald Brook said to me about grief: There is no end to grief; it just comes upon one less suddenly as the years go by.

This family is one of the rare few that did not succumb to emotional pressures following a child's death, who 'stuck together' as Brian puts it, he and Violet and the kids, living in the same house for thirty years before shifting to another suburb eight years ago. He finds it strange, he says, to have watched Allen's brothers and sisters grow up, to see how they've turned out, to know that Allen would be forty-two now. The dreams that wake him are still the same, the sort of dreams you wouldn't wish on anyone, the kind you realise are real as soon as you open your eyes. He is grateful to the police, who visit him about three times a year and who keep him informed of any changes in the investigation. They have assured him, he says, that Derek Percy is completely cleared from their suspect list for Allen's death.

There is little more to say beyond thank you and farewell. 'We don't speak to the press,' Brian says. 'Never have. So, I think we'll just leave it at that, then.'

Acting Superintendent Sheehan admits that no behavioural aspects at Redston's crime scene correlate with the Tuohy murder. 'Look at it logically. Tuohy was only a few months afterwards and the two just don't match up. He wouldn't have started with behaviour shown at Redston's crime scene and escalated so quickly to that seen at Tuohy's. It's just not realistic.' This is not an opinion shared by all of Sheehan's Victorian counterparts, who have not ruled out Percy for Allen's death. Sheehan went to Victoria in 2007 when documents were recovered from the warehouse but there was nothing found amongst it to implicate Percy in the Redston case. 'From my visit to Victoria when I met with Newman and the team from Operation Heats, it is fair to say that some members of that team believe Percy could be responsible,' he says. He is angry when I tell him I have spoken to Brian Redston.

'I hope that was before you first spoke to me. I particularly asked you not to contact the family.'

'It was, yes,' I assure him. 'It was months before I spoke to you. But with respect,' I add, 'if I listened to every police officer who warned me not to contact victims' families or other people, I would never get any material for my book.

'Actually,' I laugh, to break the tension, 'it's taken me months to even get this information from Federal Police.'

'Yeah, but can you feel the love now?' he quips.

We make small talk for a moment or so, before he wraps up the conversation. 'Okay. I think that about covers it. Will that be all?'