In a brief talk with mediapersons here, he said a final opinion on the incident can be had only after getting the medical certificate.
V K Biju (38), personal staff of the Minister, and his friend Shamsuddin (29) were arrested on February 11.
Biju was suspended from service in the wake of the incident.
Police had said there was an attempt of rape before she was suffocated to death.
Biju told police the woman had threatened him she would disclose his alleged affair with a lady which prompted him to kill her.