According to a doctor in the emergency room of Chungbuk National University Hospital (quoted by Chosun), the man had a:
“blot-shaped wound caused by a shock or impact below his left chest. The X-ray showed that his heart and lungs were damaged. It seems he died due to severe impact from a blast, considering that his ribs were fractured. The accident was highly likely caused by an explosion, given the damaged conditions of his shirt,” he said. “The area near the wound indicated it was burned by a blast."
Judging by to the photos of the device, it is presumed that the phone in question was an LG model. However, such an assumption will quickly spark Korean phone makers to state once again that fake versions of their models are being sold at cheaper prices by Chinese manufacturers. Furthermore, there’s no information regarding the manufacturer of the battery.
On the other hand this is the second case in which an exploding mobile phone proves to be fatal. Back in June the press reported an incident in China, where one man also killed by the defective phone he had in his chest pocket.