An imprisoned Army sergeant who committed abuses that led to the death of an Army private in April 2014 is alleged to have committed similar abuses on fellow prison inmates.

Identified only by his last name Lee, the sergeant is reported to have sexually harassed, attacked and committed other acts of cruelty against at least three inmates from February to August this year before the matter was brought to light. Lee was moved from an eight-person cell to a single-person cell in August.

Lee received a 45-year sentence last October for causing bodily injury leading to the death of Private Yoon. He was acquitted of murder, however. On appeal, his sentence was commuted to 35 years although the court this time found him guilty of murder. The original sentence was shortened as Lee showed signs of remorse. The case is now pending at the Supreme Court.

The atrocities that Lee committed in the military prison can hardly come from a person who expressed remorse and shed tears in the courtroom. The violence and human rights abuses that Lee perpetrated within the prison walls were almost identical to those he committed against Yoon who died as a result.

The victims allege that the prison guards ignored the problem even when they became aware of the abuses and did not take action to stop Lee. Asked by the investigators why they did not report the problem earlier, the victims are reported to have said that they were afraid and did not know how to alert the authorities. In fact, they had never heard about the complaints box in the prison through which they could report their grievances. Just as Yoon was unable to reach out for help, the abused inmates did not know where to turn to.

It is deplorable that Lee was allowed to continue his crime in the military prison for months without any intervention from the authorities. In fact, the crime came to light only after a victim requested an interview with an officer.

Experts explain that the lack of professionalism in the military prison may have contributed to the problem. The prison is manned by military staff — conscripts serve as prison guards and officers are assigned to prison duty on rotation. It is not surprising, then, that the conscripts in their early 20s who receive very little training before they are posted as prison guards would be reluctant to cross paths with a hardened criminal like Lee.

Also problematic is the fact that Lee was locked up with inmates serving time for much lesser crimes. Given the nature of Lee’s crime, the prison officials ought to have isolated him from younger inmates whom Lee found easy to intimidate and abuse.

The military investigators should not only look into Lee’s trail of abuses but also discover why the system failed to protect the inmates from Lee’s despicable crimes.