A casual perusal of Ashley Dyball's social media postings last year might have suggested a quintessential young Australian male enjoying his formative years in Brisbane. 
The 22-year-old appeared happy, indulging in a passion for hotted-up cars, socialising with his mates at pub sessions and being deeply committed to the sport of weightlifting, having previously successfully represented Australia at the Oceania Powerlifting and Bench Press Championships in 2013.
His family seemed a beacon of solid middle-class respectability, running a successful small business in the city's northern suburbs.
So what then made him suddenly decide to travel thousands of kilometres across the world and risk his life joining a Kurdish "People's "Protection Unit" known as the YPG of Rojava engaged in a deadly battle with Islamic State terrorists in Syria?  
Dyball isn't saying anything much at all since he was deported from Germany, where he was taking a break from the combat zone, and returned against his wishes to Australia on Tuesday.
His silence is understandable, as he could face charges relating to foreign incursion offences designed to stop Australian nationals from going overseas and joining terrorist groups like IS. Following his return he was briefly detained by the Australian Federal Police (AFP) before being released without charge.
So far three Australians have come under investigation for either assisting Kurdish forces or attempting to travel to join the group. Former Northern Territory Labor Party leader Matthew Gardiner and Dyball are being investigated over their roles with  Kurdish forces while Melbourne man Jamie Williams, who was stopped trying to travel to the area, has been charged with an offence relating to preparing to enter a foreign country with the intention of engaging in hostile activities. Two Australians Reece Harding and Ashley Johnston have been killed after joining the Kurdish forces. 
Dyball confirmed via brief comments on his Facebook page this week that he was "still under investigation". 
But some possible motivating factors for his shock move can be gleaned from his friends and social media postings that he made under the alias of Mitchell Scott, along with some emotional statements that he made during a brief media interview when he was reunited with his parents in a Kurdish-held area in Syria, where he was apparently working with the Kurdish YPG militia group Lions of Rojava.
One significant incident Dyball flagged on Facebook occurred in 2010 when he revealed that he had suffered a bad setback, failing in a bid to join the Australian Army after being medically discharged before he completed basic training.
The incident appeared to be devastating as he had previously posted on the eve of the course in   July 2010 that it was "time to start the beginning of the rest of my life".
Then three months later he wrote that he was "shattered", explaining to friends that just as he was nearly through his training at Kapooka he "bulged a disc" in his back while reaching for his water bottle after a pack march. 
A few months later he was "back working for mum and dad till I can get a job or something to keep me occupied" and posting about things being "boring".
It was a situation that a close friend of Dyball says should not be taken too seriously.
"I don't want people to think he was obsessed with guns and things. He bounced back from it pretty good," the friend, who asked not to be named, said.
The friend, who became close to Dyball in his teens in Brisbane, said that it was as a result of the back injury that Dyball to took up weightlifting to aid his recovery.
"And as you can see he's a pretty hard guy to keep down. He started a weight program and became a bench-press champion."
In other 2010 Facebook posts Dyball said that the discharge was only "for a year or two" and he told a mate that he would reapply to join up in 2012.
But whether he was knocked back or did not reapply in 2012, the Defence Department has refused to say. Defence has confirmed Dyball was a recruit who did not complete "initial training".
The friend said he believed Dyball did not reapply to the army.
He believed that Dyball's motivation lay with his desire to help people, he said.
"He was one of the nicest guys. If you did things right by him, he would do anything for you."
Certainly comments made by Dyball during in an interview he did for 60 Minutes in Kurdish-controlled Syria, along with some other social media posts, suggested he was motivated to help those suffering from the attacks by IS.
"I'm sure everyone not dumb when it comes to ISIS [another name for IS] extremist ideology," he said during the interview last month when asked about why he was there.
"Just look at what they put up on the news ... videos they make, people that do that are not mentally stable, they are animals.
"I call them cancer because no one likes cancer and the only way to stop cancer is by killing it completely."
Videos posted by IS and other organisations battling for the hearts and minds of potential recruits have been cited by many as providing potent motivation for all sides.
Gold Coast surfer Reece Harding who travelled to Syria around the same time as Dyball in   May to join the same Kurdish group but died in a landmine explosion in   June, was motivated by similar media, according to his parents.
Harding's father, Keith, said he thought Reece had been exposed to information on the internet about terrorists raping and beheading women.
"I think it really did get to him in the end," Harding told the ABC after his son's death.
In   June this year - then in the heart of the Kurdish-controlled region - Dyball posted an explanation for his actions.
"Have to make this short and sweet limited times at the moment first don't believe the media they're a bunch of headline grabbing morons don't believe anything unless it's from me you all know me thirdly this is my life my decision I can sit at home doing nothing with myself or I can stay here and help liberate the innocent children and women to give them a better chance at life that we all so luckily have," he wrote.
"The shit you see here is nothing like you see on the bias news reports the Islamic State must be stopped and if it means I can't come home, f--- it.
"I don't care one life to save many this isn't for attention for myself this is to help raise awareness for the the innocent people here trying to live a life that are slaughtered on a daily basis family friends I love you all just understand this is my life my decision.
"I'll try and individually reply at a later date but as you can all imagine my facebook has gone a little crazy take care all much love."
Soon after having his mate, Reece Harding, killed in a landmine explosion Dyball was posting images of atrocities carried out by IS including a photo of dead enemy fighters with the comment: "Personally I find this lineup better then stereosonic (dance festival) and the best part was only one guy had his shirt off."
In late   July he wrote about visiting a kebab shop owner saying "he was very thankful and we spent a hour with him he gave us some of the best grillled chicken I've had in my life.
"To my western mates here you read it right grilled chicken, its the lil things in life that make you smile and in that hour there were many!"
The Dyball family have declined to speak while Dyball is under investigation.
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Dyball is not the only Australian to have been inspired to action against IS.
Matthew Gardiner
The 43 year old ex-Army, former Northern Territory Labor official, who allegedly travelled overseas to help Kurdish forces, returned to his home in Darwin in early   April. He was questioned by the AFP on his return but not charged.  
George Khamis
The Melbourne father of two returned to Australia in   March after travelling to Iraq allegedly to join an Assyrian militia group, Dwekh Nawsha, fighting against IS. He was questioned in Abu Dhabi and on his return to Australia but not charged.
Ashley Johnston
The 28 year old former Army reservist originally from Queensland was killed in   February fighting with Kurdish forces near Tel Hamis. The Kurdish community in Sydney held a funeral in his honour in   April.
Reece Harding
The Gold Coast 23-year-old left home in   May and was killed by a landmine in Syria in   June during an operation with Kurdish forces. His family believed he was doing humanitarian work.
Jamie Williams 
 The 28 year old security guard was stopped at the airport in   December 2014 after allegedly planning to travel to fight in Iraq against IS.