JEONJU -- An appeals court has raised the prison sentence to 12 years for a former civil servant convicted of raping a coworker and using a video of the crime to blackmail her into having sex with him against her will for 20 months, officials said Tuesday.

The 27-year-old had been sentenced to nine years in prison, but the Gwangju High Court upped the sentence by three years, saying he "maliciously made the victim suffer to fulfill his sadistic and perverted sexual desires."

According to court records, the man lured the married coworker to his house and raped her in August 2019. He was found to have recorded the incident and blackmailed her to film more nude photos and sex videos with him on 29 occasions for about 20 months since then.

He threatened to share the materials with the victim's husband and family whenever she rejected to meet him and blackmailed her into having sex with him. He even forced her to sign a "sexual slavery pledge" stipulating what she needs to do during sex.

Under extreme mental distress, the victim reportedly attempted to take her own life.

"The court is sincerely worried whether the victim will be able to live a proper life with her mind and body severely damaged (in the crime)," the court said. (Yonhap)