A military court ordered a nine-year prison sentence for a noncommissioned officer(NCO) in the Air Force for sexually assaulting his colleague who later died in an apparent suicide.

Handing down the sentence for a forced indecent act causing bodily harm on Friday, the court said psychological trauma from the assault seems to have been the main cause behind the woman taking her own life.

The defendant surnamed Jang was convicted for groping his colleague surnamed Lee while the two returned to base in the central city of Seosan following a private gathering in March.

Lee's superiors allegedly tried to persuade her to reach a settlement and conceal the case before she was found dead at her on-base residence in May.

Military prosecutors earlier sought a 15-year sentence, but the term was reduced after the court didn't recognize that Jang blackmailed Lee to deter her from reporting the incident through text messages. Legal counsel representing Lee said military prosecutors are expected to appeal Friday's ruling.