A 26-year-old worker at a Chinese factory making Apple iPhones died after working up to 12 hours a day, seven days a week, his family have claimed to MailOnline.
Tian Fulei was found dead on February 3 in a dormitory he shared with other workers near Shanghai at Pegatron, one of Apple's largest product manufacturers, responsible for making items including the iPhone 6.
A verdict of 'sudden death' was given in court, but no autopsy was carried out.
Mr Tian's family said he worked relentless overtime hours at Pegatron, and his death came less than two months after an undercover BBC Panorama investigation revealed how workers there worked to the point of collapse.
His sister, Tian Zhoumei, 25, told MailOnline that her brother had been healthy up until his death and blamed overworking for his demise.
Pegatron has denied a link between the death and his working environment.
The death of Mr Tian once again highlights concerns over the working conditions of lowly-paid workers feeding the world's demands for Apple's products.
The company announced it had made the largest quarterly profit in corporate history in January, posting £11.8bn in its fiscal first quarter. More than 74.5 million iPhones were sold worldwide in the three months leading to December 27 last year.
The Tian family were given 80,000 Yuan (£8,300) as a 'gesture' from Pegatron – an amount upped from 15,000 Yuan (£1,500) after police aided negotiations.
The family has since returned to their home in Shandong Province to continue farming work. They are not seeking any more money from Pegatron, but are unsatisfied with the company's response.
Mrs Tian said that her brother, an assembly line worker who earned a basic wage of 1,800 Yuan (£187) a month, died in the morning but his body was not discovered until the evening.
'The company's explanation was that he didn't go to work that day, he said he had a cold so was resting in the dorm,' she said.
'His body was examined on the night of February 3 and the time of death was established to be about nine or 10 in the morning.'
Mrs Tian, who is from a farming family living in Yuncheng County, Shandong Province, was told that an autopsy would cost her family 20,000 Yuan (£2,080) – which they couldn't afford.
She said her brother worked at the factory for around six months in 2012, then returned last November.
'When we heard the news [of his death] we didn't believe it,' she said.
'We thought they were joking, but nobody picked up his cell phone so we went to Shanghai. We demanded an autopsy but the police and the company said we'd have to pay for it ourselves. We're from the countryside, we can't afford it.'
She said that to make ends meet her brother, who had a girlfriend he had planned to marry in May, topped up his basic salary to 4,000-5,000 Yuan a month by taking on an enormous amount of overtime, which was voluntary - but the family believe Tian felt he could not turn it down.
She said the company would not let her keep a copy of his work hours records.
'We heard a lot from him about overtime,' she said. 'The company is definitely at fault. He walked in there a healthy man...as a registered employee he had to pass a full body test.
'He last called on the morning of February 1...I don't remember him saying anything about being sick but he said he worked an extra two to two-and-a-half hours every day. So, around 12 hours a day.'
Chinese law dictates that factory workers can take on a maximum of 36 overtime hours a month. Apple's guidelines state that workers should not work more than a total of 60 hours a week except for in 'emergency' or 'unusual' circumstances.
Last year, Apple told the BBC that it found that the average amount of hours worked per week at Pegatron's factories near Shanghai was around 55.
However, a report released last month from factory monitoring watchdog China Labor Watch (CLW) showed that in September, October and November last year the amount of average weekly hours worked was above 60.
The figure went down to 54.6 in December 2014, a drop CLW put down to Pegatron being informed about the forthcoming BBC expose in November, allowing them time to reduce working hours.
According to CLW, which collected 96 pay stubs in January for their analysis, in November 2014 Pegatron workers took on an average of 95 overtime hours a month: far more than double the 36 hour legal limit.
The BBC's Panorama investigation claimed to have uncovered evidence that taking on overtime was essentially mandatory, a claim backed up by CLW and an ex-Pegatron factory worker who spoke to MailOnline.
'It's definitely mandatory...on average it's about 80-90 hours overtime a month,' the female worker, who was employed by Pegatron in 2012 and 2013 and asked not to be named, said.
'Most people make their living by working overtime. I know someone who did more than 200 hours overtime a month.'
Kevin Slaten, program coordinator of CLW, said: 'There is a tremendous amount of mandatory overtime. In some cases workers can choose not to do it but supervisors will say, 'That's fine, but you're not going to get one more hour overtime at all this month'.
'So you have no overtime and practically don't have a living wage, or you have too much, which can be dangerous.'
The BBC's undercover cameras showed Pegatron employees slumped over work tables, warned against falling against asleep and toppling into machines, and forced to say they were willing to take on night shifts and work standing up.
The ex-factory worker MailOnline spoke to, who was as an engineer on a higher salary than basic assembly line workers, said that she didn't see people sleeping on the job but did see night shift workers passed out.
'The supervisors are strict,' she said. 'If you're changing shifts or getting water, sure, but other than that they don't grant you time to eat or rest.
'You're not allowed to go out of the factory if you don't have written permission from your supervisor.
'I've seen young girls getting carried out on stretchers after their night shifts. They were unconscious. It happened quite often.'
Pegatron was asked by MailOnline to provide records of Mr Tian's working hours and to respond to his family's claim that he was overworked. A spokesperson for the firm gave a statement that did not address his workload but claimed that factory conditions were not to blame.
The statement read: 'Worker safety and well-being are our top priorities, and we work hard to make sure every Pegatron facility provides a healthy work environment for our workers. We are deeply saddened by the loss of Tian Fulei who worked with us as a visual inspector on the assembly line in our Shanghai facility.
'We investigated the circumstances of this case immediately, finding no link to the work environment. We provided support and assistance to the Tian family and our thoughts remain with them at this difficult time.'
MailOnline asked for Apple's response to the death of Mr Tian, claims that overworking contributed to his death and the average Pegatron working hours estimates CLW published in their February report.
A spokesperson for Apple's Supplier Responsibility department said the company would look into the death-related claims but refused to comment directly on them.
Deaths linked to suspicions about overworking at Pegatron’s factories near Shanghai, where around 80,000 people are employed, are not new. In December 2013 Apple sent medical experts there after an unspecified number of workers died earlier that month.
In October that year a 15-year-old boy who worked there died of pneumonia just over a month after taking the company's pre-employment physical examination.
In 2010, 14 workers at a Chinese factory in Shenzhen owned by Foxconn, which also makes Apple products, committed suicide following complaints about conditions there.
Neither Apple nor Pegatron Shanghai have released information about how many of their workers have died while employed by them. CLW fears that the cases that have come to light are the tip of the iceberg.
'These are only the cases we now about,' said Mr Slaten. 'We've seen these before – people who seem fine and just say they're tired, then they die two days later.'
Mrs Tian said: 'We still want to know [what happened]. But we don't have relatives in Shanghai...our power and the company's power, they are not in the same ballpark. There's not even a hint of hope we can get to the bottom of this.'
Mr Slaten said that Mr Tian's case highlights the helplessness of workers at Pegatron.
'They have no choice but to buy into the system,' he said.
'Even when we ask them, "Do you need to do so much overtime?", with such low wages they usually say they want more hours, because otherwise they can't survive.'