Franziska Blöchliger, 16, was raped and murdered in Tokai Forest.

"It could not have been me, there were multiple semen [sic] inside her. I'm only one person. I was alone," said murder-accused Howard Oliver in Afrikaans in a pre-recorded video clip shown in the Western Cape High Court heard on Monday morning.

Prosecutor Lenro Badenhorst says a post-mortem did not support Oliver's argument as no semen was found in Franziska Blöchliger private parts, reports News24.

Oliver, 28, stands accused of murdering 16-year-old Franziska when he allegedly robbed her on his way home from work on 7 March last year.

Franziska, 16, had been jogging in Tokai forest when she robbed, raped and brutally murdered.

In one of the video shown, clips Oliver took investigative officers to the scene where he confessed to attacking her and trying to steal her iPhone.

Last week, the court heard that Oliver fastened Franziska's wrists with one shoelace and tied another around her mouth. He also acknowledged that her pants were pulled down, but said that her underwear was not removed.

"I made double sure she was still breathing," he said in the clips.

Oliver said he tied her up in such a way that she would able to loosen the shoelaces afterward.

"She [Franziska] can get back her cellphone, but she can't get her life back. I only took her phone," he said.

The trial continues.