18-07-2025
Detective reveals the subtle clue that gave away Daniel Morcombe's killer Brett Cowan immediately
From the minute retired detective Dennis Martyn drove up the driveway of paedophile Brett Peter Cowan's house just two weeks after the disappearance of 13-year-old Sunshine Coast schoolboy Daniel Morcombe, he knew something was off.
'His house was on the front of the block,' he explains, 'there was a lot of - I wouldn't say kids' toys - but there were a lot of things around in the yard, like little windmills that Cowen had made, all sorts of things he would take to markets and sell. But they were painted in such a way that to me, I thought a kid would want them, you know? There were butterflies on the blades of the windmills and all this sort of stuff.'
'I said to [detective Ken King, Martyn's partner] straight away: 'that's a bit strange, mate. It just looks like a kid's area'. And I knew he didn't have any children at that age.'
But it was the conversation Martyn would have with the house's inhabitant that would change everything.
From the moment Martyn and King left Cowan's house that day in December 2003, they were convinced he was their suspect.
Sitting down with fellow ex-detective Gary Jubelin for an episode of Jubelin's podcast I Catch Killers, Martyn recalled the moment, over 20 years ago, that convinced him Cowan was the perpetrator.
It was two weeks since Daniel had last been seen waiting for a bus, on his way to buy Christmas gifts for his family.
Martyn, who at the time was working as a senior constable on Task Force Argos, a team responsible for investigating child sex offences, had been handed the file.
'At that time, they gave you a series of folders [full] of convicted, released sex offenders in that area,' he tells Jubelin.
'Our job was to go around and check out their bona fides. If they said, 'I was at the shop at that time', you would spend half the day going to the shop, getting CCTV to verify their alibi. That's how we came up, and one of the people in the file was Brett Peter Cowan.'
Martyn was already aware of Cowan's criminal history, most notably his 1993 conviction for the horrific rape of a six-year-old child in the Northern Territory.
He was also aware that a white 4WD with a black snorkel had been seen near the underpass where Daniel Morcombe was last seen, which matched the description of Cowan's vehicle.
Once they'd arrived at Cowan's house, the two officers began questioning the paedophile about his whereabouts on the day of Daniel's disappearance.
After admitting he 'might have gone in and picked something up at Nambour' around the time Daniel was last seen on the Nambour Connection Road, Martyn says Cowan was 'acting cocky.'
'He was a skinny sort of fellow, and every movement was accentuated, that's sort of the way he was,' Martyn recalls. 'He was very cocky and straight away I didn't like him. I said to Ken, 'just keep an eye on this bloke, mate'.'
'I said, 'did you happen to see a little child with black hair on the underpass from the other side near the bus stop?' [Cowan said] 'No, no, no. Not at all. Never saw anybody.' I said, 'well, did you see a white 4WD with a snorkel on it?'
'No.'
'I said, 'do you think it is a coincidence that you drive a white car with a snorkel on, and it's a four wheel drive, and someone's saying they saw something similar on that side of the road?''
Martyn decided it was time to apply more pressure.
'I said, 'you're a paedophile. A bad one by the sounds of it. And Daniel is in your [preferred] age group'. And he goes: 'well, he looked it.''
'I said, 'did he? That's strange. I thought you said you didn't see anyone,' [and he said], 'oh, well I might have pulled over.''
'I said: 'so now we've established two things. First, you've pulled over and you reckon you've seen Daniel, and [second] you're a liar. But we all know you're a liar, because paedophiles are liars.' And then he started to get cranky.'
In spite of this, and the officers' conviction that Cowan was responsible for Daniel's abduction, it would be another eight harrowing years for the Morcombe family before their son's remains were found, and Cowan apprehended after a lengthy undercover sting operation which became the subject of the 2022 Netflix film The Stranger, starring Joel Edgerton.
But it wasn't for Martyn and King's lack of trying.
'Ken briefed the major incident room the next day,' Martyn explains.
'And that was it. It was quietly dismissed.'
'So that people understand the working of a strike force, whether it be in Queensland or down here,' explains Jubelin, 'all that information comes in at briefings. As you said, Ken briefed the major incident team and said, 'OK, this is our take on it'. You've done the report, submitted that, and you would think that there would be some priority given to what needs to be done.'
'At that point in time, our report dictated that that should have been the case,' agrees Martyn. 'My reports are reasonably concise and very clear and accurate in relation to what recommendations should and should not be done.
'The recommendations on that report were very clear - basically, he's your main suspect. If he's not, he should be, and everything should be done to rule him in rather than trying to rule him out … but they never even went and seized his computers.'
Brett Peter Cowan is currently serving a life sentence for the murder of Daniel Morcombe and will be eligible for parole in 2031.
