Fotuaika had a long, handsome face and the solid build of his Tongan forebears. He was bench-pressing 90 kilograms, according to Joel Luani, the player who partnered him in the gym that day. This was not much of a challenge for Fotuaika. "He does it every other day of the week," says Luani. "He does it easily. He could lift 160 kilograms." But Fotuaika suddenly gasped. "It was a split-second thing," Luani says. "He went to lift and then he couldn't lift. I grabbed the weight and pulled it back up."

The team physiotherapist, Peter Moussa, could see that Fotuaika had torn a pectoral muscle, one of the large, fan-shaped muscles on either side of the chest. "I assessed him," Moussa says, "and I said, 'Okay, buddy, it's the pec.' " This was an injury that could sideline the up-and-coming prop for several months. Still, Moussa was surprised by the reaction of Fotuaika, who was normally a stoical, self-contained young man. "I said, 'Is it the pain? Is that why you're crying?' He said, 'No. It's just stinging a bit.' " The physiotherapist pointed out that they wouldn't know the extent of the damage until Fotuaika saw a doctor and had a scan the following morning. Moussa fitted him with a sling and tried to comfort him. "I put his forehead on my shoulder and I had my hand around his neck. I said, 'It's okay, buddy. It's all right.' " Over the phone, I hear lingering bewilderment in Moussa's voice. "You know, it was just strange," he says. "It was really strange."

When Fotuaika got to the change rooms, his friend, Ben Murdoch-Masila, offered him a lift home. Murdoch-Masila did his best to cheer him up, reminding him as they drove away from Concord Oval, in the city's inner west, that an injury wasn't the end of the world: Fotuaika had his whole career in front of him. But Murdoch-Masila remembers thinking he wasn't getting through to him: "He was really upset. He said, 'Mate, let's go for a beer.' I said, 'Your injury's too fresh. It will interfere with your healing.' " In any case, the two didn't have much time. Murdoch-Masila was expected to join the rest of the Wests Tigers squad for a recreational cricket match back at the oval that afternoon, and Peter Moussa wanted Fotuaika returned to his care. "I was going to take Mosese," says Murdoch-Masila. "I asked him if he wanted to get changed at my house. He said, 'No, I want to go home.' " So Murdoch-Masila dropped Fotuaika at his rented townhouse at Merrylands at 12.45pm. "I told him I'd come back to pick him up in about half an hour."

When Murdoch-Masila and another player returned to collect him, Fotuaika did not answer the door. Nor did he pick up his phone. His team-mates were puzzled but not particularly concerned - maybe he had gone out or fallen asleep. They called Wests Tigers coach Mick Potter, who told them to continue on their way to the cricket match. "I said, 'It's not your problem to find Mosese,' " recalls Potter, who, along with Moussa, tried repeatedly to phone him over the next few hours.

Fotuaika's body was found in the garage by his girlfriend, Shanice Alaiasa, when she got home soon after 6.30pm. "Shanice rang me, screaming into the phone, 'He's gone,' " says Nicole Heu, Alaiasa's mother. Heu wanted to believe her daughter meant that Fotuaika had packed his bags and left, but somewhere in the pit of her stomach she realised that wasn't the message at all. "I said, 'Shanice, calm down. What's happened?' She said, 'Mosese is gone, Mum.' And I couldn't talk to her. I handed the phone to my husband. Then within five minutes the police had arrived, before the ambulance."

By the time I meet Alaiasa, 20, it is three weeks since she dialled 000 with trembling fingers. Tall and dark-haired, she is resolutely composed. And six months pregnant. A law student, she has deferred her studies and returned from Sydney to the Gold Coast to live with her family while she awaits the birth of Fotuaika's child. "When I packed up the house, I searched every-where for a note - even a little scribble somewhere," she says. "But at the same time, I know Mosese, and I know he's not going to spell out his emotions. Even though I was looking, I didn't expect to find anything." She pauses. "It's just frustrating, having a big question mark."

What drove Mosese Fotuaika to end his life? Alaiasa tells me she and his parents went to see Wests Tigers CEO Stephen Humphreys in the hope he might be able to help them find an answer. Humphreys was patient and sympathetic, she says, but they came away little the wiser. A successful young footballer injures himself in the gym then goes home and commits suicide: it doesn't make sense to the people who loved him. "We want facts," Alaiasa says. "Just to put our souls at ease, really."

Jo Hallett is the deputy principal of Keebra Park State High School, on the Gold Coast, which has a specialist rugby league program and a close relationship with Wests Tigers - each year, the club recruits five or six of its graduates. "The most beautiful boy," Hallett says of Fotuaika, who as a student often stayed at her place during the week rather than make the long trip home to Brisbane. When he moved to Sydney to join Wests Tigers, she and her husband remained in close touch with him, and had booked to fly down for his 21st birthday in late March. The visit was to be a surprise, she says. As a gift, she had compiled an album of photos and newspaper clippings about his sporting triumphs.

Hallett learned of Fotuaika's death from Nicole Heu, who called her just after getting the news from her daughter. One moment the deputy principal was standing with the phone at her ear, the next her legs had given way and she was sinking to the floor. "This boy was like my second son," she tells me. "And I never thought he would do that." Since then, Hallett has done a lot of thinking. She has replayed conversations in her head, re-read emails, analysed large and small incidents. Like Alaiasa, she has been searching for clues. And a motive. What she has come to realise is that Fotuaika, who stood 181 centimetres tall and weighed 104 kilograms, was much more fragile than he appeared. "Mosese was a very intense person," she says. And "he had plenty of things he kept to himself".

Ben Murdoch-Masila, who considered himself to be Fotuaika's best mate, has been left wondering how well he really knew him. "He never told me his feelings," Murdoch-Masila says. "I think it was how he was brought up. A lot of Islanders are like that - they don't want to be seen as a weak person, or soft."

They certainly don't look soft on the football field. Speakers of Pacific Island languages accounted for less than 0.3 per cent of the Australian population in the census of 2011, yet the same year almost 30 per cent of contracted NRL players were of Islander heritage: Samoans and Tongans mostly, with some Fijians in the mix. "They've got the physique," says Peter Horton, a senior lecturer in human movement studies at the Townsville campus of James Cook University. More than that, they have the speed, the agility and the ball skills. In short, says Horton, whose article Pacific Islanders in Global Rugby appeared recently in an academic sporting journal, "they're bloody good at it".

Fotuaika was born in New Zealand and grew up in Gisborne, on the North Island, where his parents had settled after moving from Tonga. One of 10 children, he started off playing rugby union - the Kiwis' national obsession - but switched codes after a visit from a persuasive rugby league scout. At the family's present home, a modest dwelling at Wellington Point in south-eastern Brisbane, his mother, Ilaisaane - known as Lisa - says the decision to come to Australia in 2007 was made partly so that the then 15-year-old Mosese, her oldest boy, would have a better chance of pursuing a career in his chosen sport. "Mosese was always quiet," she says. But he was also ambitious, and hard-working. "He was always a guy who wanted to be the best at what he was doing."

In the league program at Keebra Park High, Fotuaika was one of many talented teenagers of Islander descent: his team won the national inter-school league competition in 2009. To Wests Tigers recruitment manager Warren McDonnell, he stood out from the pack: "He was a strong kid. Great defence. Strong carrier of the ball. Fit." It was at Keebra Park that Fotuaika met Shanice Alaiasa, a fellow student. "There was no one else for him," says Jo Hallett, who watched the romance blossom. "This was it. And she idolised him."

At 19, Fotuaika signed a contract with Wests Tigers, which meant moving away from Alaiasa and the warm embrace of his big family. He was wretchedly homesick. "Mosese hated Sydney just because his family wasn't there," Alaiasa says. "I know a lot of his mates who are Tongans, Samoans, and family is such a big thing for them." Lisa says she phoned her son often: "He always says, 'Mum, you don't know how hard it is.' "

Last year, Fotuaika's second season with the club went better than the first. Alaiasa joined him in Sydney and they got a place together. He played a key role in the Wests Tigers' under-20s team's victory in the National Youth Cup, even scoring a try in the grand final - a particularly impressive feat for a front-rower. Perhaps best of all, he was awarded a place in the club's first-grade NRL squad. "It's unusual to have someone that young in your full-time squad," says Wests Tigers boss Stephen Humphreys. "He was there because of the potential he showed and the attributes that we could see in him."

Fotuaika had not yet been selected to play in the firsts' side, but as the 2013 kick-off approached, it seemed clear that it was just a matter of time. Lisa says that when she spoke to him on February 25, "he was saying, 'Mum, everything is all good. Maybe one or two weeks, then I'll debut.' That was his goal. That was the ultimate thing for Mosese, to debut for the NRL."

Lisa and her husband, Penitani, were not yet aware that their son's girlfriend was pregnant. Alaiasa says he had been putting off telling them until after he played a first-grade match, figuring they would be so proud about his debut that they would be pleased about the baby, too. Alaiasa had been dismayed about the pregnancy initially, not only because she had intended to wait until later to have children but because she believed that Fotuaika, poised on the brink of the big time, needed to be able to give his full focus to football: "I said to him, 'I don't want to distract you.' And he said to me, 'No, the baby is a blessing. We're having the baby for a reason.' " On February 27, he went along when she had an ultrasound scan and spoke later to her mother, Nicole Heu. "He said he could hear the heartbeat and, 'Wow, wasn't that amazing?' " Heu remembers. "He was happy."

The next morning, Fotuaika left home at 5.30am to go to training. Friends were struck by his good spirits. "Around that time was probably the most I've ever heard him talk," says Joel Luani. "We had a break during the day and we went up to the pub to watch the footy on TV. We were laughing and telling jokes. Everything seemed fine."

Coach Mick Potter was in a meeting in an office near the gym when he heard that Fotuaika had injured himself. "I poked my head out and was watching the physio assess him," says Potter, who decided Fotuaika was in Peter Moussa's capable hands and he would wait until later to talk to him. But by the time he came out of his meeting, Fotuaika had left. Ever since, Potter has been asking himself whether he made the wrong call: "Should I have gone out and spoken to him then? Would that have made a difference? You just don't know."

At about 5.30pm, Nicole Heu was called by her daughter, who said she had been thinking about baby names and texting them to Fotuaika. The odd thing was, he hadn't responded. As Heu recalls: "She said, 'He must be really focusing on his training.' " A little later, Alaiasa spoke to Ben Murdoch-Masila, who told her about Fotuaika's torn muscle. More than anyone else, Alaiasa was aware of the full import of this news: not only did she know how badly her boyfriend wanted a first-grade game, she knew the despair he had felt over a string of previous injuries. For much of the summer, he had been recovering from a hurt knee. Now this. "I knew it was going to devastate him," she says. "I was straight away texting him, saying, 'I hope you're okay. It's all right. I'll try to call you.' " Alaiasa then headed for home, hoping he had simply decided to turn his phone off. Stuck in bumper-to-bumper peak-hour traffic, she felt panic rising.

It was probably too late by then anyway. "I believe the circumstances would suggest that, considering the teammates could not raise him at lunchtime," NSW Police Detective Inspector Adam Phillips says in an email, going on to point out that the events of February 28 may yet be subject to an inquest: "We are still preparing statements for the coroner and this would include statements from our crime scene officers who would provide an estimated time of death." Phillips says police believe Fotuaika killed himself - he was found hanged - but "we are not sure as to why this occurred, which is the real tragedy of a lot of suicides".

Like everyone who cared about Fotuaika, Nicole Heu has been struggling to understand his state of mind. "We know he took off his shoes and put his bag in the laundry where he always puts it," she says. He also plugged his phone into its charger. "Then I think he got angry at himself."

Former rugby league player Nigel Vagana says there are two things to remember about people of Pacific Island descent. First, "the connection to family is a lot stronger than in most other cultures". Second, "we have a communal mentality: 'What's mine is yours.' " Vagana, an NRL education and welfare officer, says many Islander footballers feel financially responsible for their extended clans. It's not that they are forced to provide for them: they want to do that. "We put family above everything else," he says. "A lot of players obviously love the game, but it's actually the opportunity to support the family that keeps them in the sport."

According to Fotuaika's friends, he felt this sense of obligation very strongly. "He was sending most of his money back to his family and only keeping a little bit for himself," says Ben Murdoch-Masila. "He was a good person. A good son." Joel Luani believes Fotuaika's distress about his latest injury stemmed from his assumption that it would lower his earning capacity - not just in the immediate future (when he would lose the opportunity to supplement his $75,000 salary with $3000 first-grade match fees) but in the longer term, because it was less likely that Wests Tigers would re-sign him if he couldn't get onto the field and demonstrate his value to them. "He probably felt like he'd let his family down," Luani says, "even though he hadn't."

Academic David Lakisa, who called his master's dissertation The Pacific Revolution: Pasifika and Maori players in Australian Rugby League, makes the point that the collectivism of Islander culture means footballers don't just share dollars with their kin, but the honour of belonging to the NRL. "When I debut, it's not my debut," says Lakisa. "It's my mother's, my father's, my grandparents', my great-great-grandparents', who are watching over me now. It's their debut."

Aspects of Fotuaika's personality were typically Tongan. His reserve, his humility, his deference to elders - these are qualities fostered in young people raised in Islander families. They were traits that endeared him to Jo Hallett at Keebra Park, but she can see that they may not always have helped him in the rough and tumble world of rugby league. She knows, for instance, that he was taking a while to adjust to life in the Wests Tigers' senior squad. A large part of the problem was his shyness, she says. He felt overawed by the older players, including stars like Benji Marshall (another Keebra Park old boy) and Robbie Farah. Hallett had urged Fotuaika to learn to look them in the eye, and to lighten up a little. "I think you are sooo hard on yourself," she had written to him in 2011. "You find it very hard to let go and relax. You would rather do a mean gym session than spend quality time with the boys which would contribute to the trust and tightness of the group."

No one at the club spent more time in the gym than Fotuaika, and Shanice Alaiasa cannot imagine that anyone worked harder away from it. After a full day's training, he would come home and train some more, she says. "While I'm cooking dinner, he's going for an hour's run. Then as I'm serving dinner, he's doing push-ups and sit-ups in the lounge-room in front of the TV." He felt he could not afford to rest. "You're always going to be looking over your shoulder, I think, in football," Alaiasa says. "Worrying that someone bigger and younger and fitter than you is going to come through and take your position, and then you're going to be pushed to the side."

Fotuaika had focused so single-mindedly on becoming a professional footballer that he had acquired no other qualifications; he didn't have a back-up plan. "There was nothing else he could have done, really, besides rugby league," Ben Murdoch-Masila says. "That was the only thing he was good at."

At James Cook University, Peter Horton says both rugby codes - league and union - have been transformed by the influx of dazzling performers from Pacific Island nations. "They're some of the most colourful and dynamic players, the most attractive players," Horton says. And their crowd-pleasing ability has contributed significantly to the sports' financial success. But Horton suspects that in the big business that is modern rugby, young Islanders are sometimes regarded as commodities rather than as vulnerable human beings. "If you're making a lot of money out of these kids, you've got to develop them holistically," he says. "You can't just think about their side-step techniques or their tackling techniques."

Reactions to Fotuaika's death differ. Nicole Heu tells me she is both sad and furious. In her garden the other day, she took out her rage on a leaf-blowing machine that wouldn't start: "I picked it up and I threw it. I was like, 'Mosese, I am so angry that you did this because you didn't have to!' I said, 'Mosese, all that extra training you did was for nothing!' " For a while, Ben Murdoch-Masila was plagued by nightmares. He still agonises over the possibility that he might have saved his friend if he had tried to get into the house instead of going to the cricket match. Joel Luani can't stop thinking about the moment in the gym when Fotuaika realised he couldn't lift the barbell. "I try to convince myself that there's not much I could have done," Luani says. "But I feel guilty."

He isn't the only one. "We've all been through that process of questioning ourselves, about why we didn't pick up on things," says Stephen Humphreys, who with 70 players and staff flew to Brisbane for the funeral on March 7.

"It was a massive shock, obviously, and it's fair to say it had a dramatic impact on everyone."

Two weeks before Fotuaika died, his agent, Simon Mammino, had spoken to recruitment manager Warren McDonnell about his future at Wests Tigers. Fotuaika's mother Lisa says Mammino subsequently brought her the alarming news that he was unlikely to be re-signed when his contract expired in November. She was careful not to pass this on to Fotuaika, knowing how distraught he would be, but she did relay to him that Mammino had been told by the club that he needed to improve his communication on the field. Personally, Lisa thought this was crazy. "Mosese can't talk," she says. "That's just how he is. But his actions speak louder. And with rugby, you have a game plan - each person knows what to do."

Mammino tells me that the club hadn't decided whether they would keep Fotuaika. "But at that point in time, it probably was not looking in his favour." Warren McDonnell concedes he told the agent that Fotuaika needed to get better at calling to his teammates, letting them know where he was and when he was ready to receive the ball ("You can't play first-grade football and not talk on the field") but he says coach Mick Potter was already working with him on that. And the suggestion that Fotuaika's contract would not be renewed? "That's a load of crap," McDonnell says. "Mosese was always held in high regard by us, and he knew that."

Mammino regrets he wasn't closer to his client. "Listen, I wish I could have done more," he says. "Could I have rung him more? Yes." But the agent insists - and McDonnell backs him on this - that he always had Fotuaika's best interests at heart. "He was a nice, humble, quiet kid," says Mammino. "I'm traumatised and having counselling myself."

Fotuaika's parents are finding it impossible to come to terms with their loss. Lisa tells me that Penitani (whose English is limited) taught Mosese to lift weights, and that he refuses to believe a torn muscle could have led to his death. "The first-born son, he is the one the family is looking up to," says Lisa, who like her husband cannot help thinking that someone must be to blame. The way she sees it, Mosese died while in the care of Wests Tigers. "They were his second family," she says. "They came and asked us, 'We want your boy.' They were the ones we trusted to look after him."

In Stephen Humphreys' office one afternoon, the subdued chief executive tells me the club has always looked out for the young players it recruits from interstate, but that attention to their welfare will now be intensified. Beyond that, he doesn't know what to do or say about Fotuaika's death. "I was sitting here with his parents and Shanice and they just couldn't understand it," he says. "They were looking for answers. All I could say to them was, 'I'm with you on that. I don't have the answers, either.' "

Injury, homesickness, fear of failure, an unplanned pregnancy ... all may have contributed to Fotuaika's decision to take the action he did. But it seems to Shanice Alaiasa that, whether taken singly or in combination, they do not constitute an explanation. "It's hard, especially with the baby coming," she says, her voice wobbling for the first time. "What am I going to tell my kid?"

Jo Hallett is stuck with the image of Fotuaika, dressed in his Wests Tigers suit, lying in his open coffin. He barely fitted into the casket, she says. "He was such a big man." And in many ways, such a fortunate one. "He had everything going for him, but he didn't see that."

Lifeline: 13 11 14.

This article originally appeared in Good Weekend. Like Good Weekend on Facebook to get regular updates on upcoming stories and events – www.facebook.com/GoodWeekendMagazine