Infanticide (Pembunuhan Anak Sendiri or PAS) is the intentional killing of an infant from birth to 12 months. This crime is considered as unique in nature. It is unique in the sense that the perpetrator of the murder is its own biological mother. Furthermore, the motive for infanticide is unwanted child. The biological mother, in addition to being afraid to be found out to give birth to a child, resists to have a child born out of wedlock. There are approximately 30-40 cases of infanticide (Pembunuhan Anak Sendiri or PAS) every year and 90-95% of them are mechanical asphyxia cases. 5-10% of them are cases of blunt head and sharp violence to the body (1 case in an estimated 6 years). The case of baby X was discovered by the police and taken to the Forensic and Medicolegal Installation of the Deli Serdang Regional Hospital, Lubuk Pakam, on 11th February, 2020 at 1 P.M. The victim was found by nearby residents on the riverbank. This was immediately reported to the local police, and a Visum Et Repertum was then requested. The age of the baby was estimated eight months based on the De has formula. It was born alive and viable. It breathed, and did not receive treatment. Its estimated lifespan was one hour. The cause of death was skull fractures due to blunt trauma, which caused damage to the brain tissue. Therefore, all functions of body's organs were impaired, accompanied by pressure on the chest that caused air blockage in the respiratory tract and fractures of the ribs.