An appellate court on Thursday reduced the prison time by eight years for a former college professor who killed his estranged wife then disposed of her body in collusion with his lover.

The Busan High Court's sentence of 22 years' imprisonment came after a local district court earlier handed down a 30-year sentence to the 54-year-old man surnamed Kang, who was formerly a professor of computer criminology at a university in South Gyeongsang Province.

The high court also halved the prison term for his 50-year-old lover known only as Choi, from 10 years to five.

Kang was indicted last year on charges of strangling his 50-year-old wife in his car at a hotel parking lot in the southern port city of Busan on April 2, then placing her body in a bag and throwing it into a river in the city.

He meticulously plotted and carried out this crime along with his lover, according to court records. Choi accompanied Kang in picking a place from which he could throw the body and helped him carry the corpse following the murder.

"The original verdict was too heavy, considering the fact that Kang has no past criminal record," the appellate court said.

At the time of the killing, the married couple was in the process of getting a divorce after a year-long marriage.

The victim was first reported to have gone missing, but police opened an investigation after her body was found afloat near an island in the river. (Yonhap)