Local police found evidence to believe that a man in his 50s who died after swimming under the influence, had in fact been forced to swim by another man.

Officials said Thursday that Changwon District Prosecutor's Office indicted a man in his 40s on charges of coercion, extortion and death by negligence. The suspect is believed to have coerced the victim and another man in his 50s to follow to abide by his will.

According to investigators, the three men had consumed 22 bottles of soju before they went to a park in Geoje, South Gyeongsang Province, on Oct. 11. The suspect allegedly ordered the two men to jump into the sea and swim. The men obeyed, an act that eventually led to the victim's death.

It was initially thought that the victim fell into the sea by himself, but police grew suspicious after finding that the victim had a bruise near his eyes. Officials found surveillance footage that showed that the victim went into the water with another man, who told police that they were forced to do so by a third man.

The second man told the police that they "had no choice but to do it, since they could get beat up (by the suspect) any time."

Further investigation found that the suspect had abused both men physically and financially, under the pretense that he was a member of a local gang. The swindled a total of 17 million won ($12,700) from the two men, forced them to fight each other, and made them do manual labor while he pocketed the profit.

The prosecutors believe that the two men had been under complete control of the suspect via gaslighting, a form of psychological abuse in which the abuser misleads the victim into a false perception of reality.

The suspect admitted to extorting money from the two men, but denied the death by negligence charge.