The Army will bring murder charges against four soldiers in the gruesome death of their junior comrade, officers said Tuesday, reversing an earlier decision to charge them with involuntary manslaughter. 

In April, the 23-year-old Army private first class, surnamed Yoon, died after allegedly being hit in his chest by six of his colleagues at a frontline unit on the east coast, while eating snacks.

The assault caused a piece of food to obstruct his airway, leading him to die of asphyxiation, the Army said, adding that his death also resulted from damage to his skeletal muscle caused by repeated assaults.

Initially, manslaughter charges were brought against four of them, with the rest facing assault charges. But the decision drew fierce criticism amid revelations that the victim had long suffered severe assaults and abusive treatment by the suspects.

"After an additional probe and legal reviews, we've decided to charge the four suspects with homicide through willful negligence, rather than manslaughter," said a military prosecutor handling the case.

"Our judgment is that his death was caused by not only asphyxiation, but the crush syndrome and secondary shock due to persistent beating," he said.

The crush syndrome refers to a medical condition in which a crushing injury to skeletal muscle leads to major shock and renal failure.

"On the day of Yoon's death, the suspects were aware that he displayed many abnormal signs in an extremely vulnerable state, but they went on beating him. Considering that the suspects have ample medical knowledge as combat medics who majored in medicine-related subjects at college, they surely were able to anticipate his death under such circumstances," he noted.

The first court hearing is slated for later this month, according to defense ministry officials.

South Korean law stipulates that those found guilty of murder face capital punishment, life imprisonment or a jail term of at least five years.

The case, which was brought to light belatedly in a media report, followed a series of incidents that have laid bare the chronic problem of bullying in barracks and a rigid military culture.

In June, an Army sergeant who had been bullied by his comrades went on a shooting spree at a border outpost on the east coast, killing five soldiers and wounding seven others.

All able-bodied South Korean men are subject to compulsory military service for about two years in a country facing North Korea across the heavily fortified border. (Yonhap)