The police investigating a freshman in his 20s accused of sexually assaulting and causing the death of a fellow student at Incheon's Inha University have referred his case to the prosecution.

The police from Incheon’s Michuhol Police Station on Friday sent the case to the Incheon District Prosecutors' Office on charges of "quasi-rape" causing death and filming the crime. They stopped short of a murder charge due to a lack of substantive evidence.

Staying silent after being asked by reporters whether he admits to all the charges as he was being transferred to the prosecution, the suspect only said that he was sincerely sorry.

The 20-year-old is suspected of sexually assaulting a female freshman inside a five-story building on campus in the early hours on July 15, before causing her to fall down from the third floor and die.

He is also suspected of filming the incident with his mobile phone, although only sounds were recorded in the video.

After leaving the victim without seeking medical help and discarding her clothes elsewhere, the suspect was arrested while he was being questioned as a witness later in the day.

While acknowledging that the victim fell to her death, the suspect has denied he pushed her off the building.