This Dec. 17, 2021 file photo shows stalking murder suspect Lee Seok-joon leaving the Seoul Songpa Police Station to be transferred to the prosecution. Yonhap

An appellate court on Thursday upheld a life sentence for a 26-year-old man for killing his former girlfriend's mother after having a grudge for reporting rape charges against him.

The Seoul High Court approved a district court's earlier sentence of life imprisonment for Lee Seok-joon for multiple charges, including revenge murder and seriously injuring his ex-girlfriend's younger brother.

Lee was found guilty of stabbing his former girlfriend's 49-year-old mother to death and inflicting serious injuries on her 14-year-old brother at their home in southern Seoul last December.

At the time, Lee was under police investigation for detaining and raping his former girlfriend after her mother reported the case.

Lee committed the murder by impersonating a parcel delivery man after finding out where she lived through an illegal detective agency. (Yonhap)