The preliminary results of a forensic analysis has found that the cause of death in the sexual assault and murder in a Seoul park last week was asphyxiation by strangling.

According to Seoul Gwanak Police Station on Tuesday, the National Forensic Service added that it would be difficult to attribute the death directly to bleeding on the victim's head as a result of external force.

The police said they are broadly investigating the exact account of the incident that led to the victim's death as well as its cause, and plans to reach a comprehensive conclusion based on the final autopsy results.

Last Thursday, a man in his 30s identified by the surname Choi physically and sexually assaulted the victim, with whom he had no previous encounter, on a walking trail linked to a park in Gwanak District. The victim died two days later.

While Choi claims that he had no intent to kill the victim despite admitting that he attacked her with brass knuckles, the latest forensic assessment is expected to be key evidence in helping investigators apply the rape and murder charge against him.

The Seoul Metropolitan Police Agency is set to review whether to publicly disclose Choi's personal information on Wednesday.