The parents of the noncommissioned Air Force officer, who took her own life after allegedly receiving push back from filing a sexual assault complaint, have urged the National Assembly to investigate the case.

The parents of the late master sergeant, surnamed Lee, made the request on Monday, saying the Defense Ministry's ongoing investigation is inadequate in unearthing the truth.

The parents said they can no longer wait for the outcome after insufficiencies in the investigation were revealed.

They underlined the need for a thorough inspection of what they called corrupt practices in an outdated military culture at the root of the incident and of the military's handling of the case.

A master sergeant was charged with a forcible indecent act and inflicting bodily harm after he allegedly groped the NCO in a car as they returned to base in the central city of Seosan following a private gathering in March.

There are suspicions that Lee's superiors tried to persuade her to reach a settlement and conceal the case before she was found dead at her on-base residence on May 22.