Postmortem computed tomography (PMCT) has been widely employed as a non-invasive adjunct diagnostic tool in forensic investigations [1,2]. Its use is particularly valuable in cases involving trauma or sharp-force injuries, providing valuable information on the depth and trajectory of wounds, hemorrhage, bone fractures, and the detection of retained foreign bodies. Moreover, PMCT enables the identification and localization of weapon fragments or traces embedded in the body, thereby aiding weapon reconstruction and classification [3-5]. Here, we present a homicide case in which a broken knife tip retained in the skull was detected using PMCT and subsequently recovered during autopsy, allowing for the identification of the suspected weapon.

An elderly man was found dead at his workplace with multiple stab wounds on the head, face, and neck. Shortly, the suspect turned to a nearby police station. Upon surrendering, he handed over two kitchen knives and a handgun-shaped gas irritant sprayer to the police. A small fruiting knife was recovered from the crime scene. Autopsy was performed on the following day. Livor mortis and rigor mortis were present on the dorsal side and all major joints, respectively. External examination revealed multiple incised stab wounds on the head, face, and neck, some of which had formed skin flaps (Fig. 1). Internal examination revealed stab wounds involving the lambdoid suture, occipital bone, and left parietal bone. A metallic fragment approximately 11 mm in length was embedded in the wound track within the parietal bone. This fragment penetrated the skull and caused a stab injury in the left lateral sulcus between the temporal and parietal lobes (Fig. 2). Additional incised stab wounds were identified on the mandible and cervical vertebrae, accompanied by massive hemorrhage resulting from injury to major cervical vessels. Toxicological analysis of the blood was negative for drugs or poisons, and the blood ethanol concentration was <0.010%. The cause of death was multiple stab wounds to the head and neck.

PMCT demonstrated a high-density metallic artifact in the left posterolateral parietal region of the skull. On axial and coronal images, the object appeared wedge-shaped, penetrated the skull, and entered the cranial cavity. Three-dimensional volume-rendered images revealed a metallic fragment embedded in the parietal skull (Fig. 3).

Homicide cases involving sharp weapons, such as knives, are common. In such incidents, blade breakage may occur because of excessive force or impact on rigid bony structures. Such excessive force can provide insights into a suspect's intent and assist in determining the manner of death. Several reports have documented cases in which broken weapon fragments are retained in various anatomical regions of the body [6-8]. Besides establishing the cause of death, identifying the specific weapons used is of paramount importance in legal proceedings. Here, PMCT enabled pre-autopsy visualization and localization of the embedded knife tip in the skull. The fragment was subsequently recovered during autopsy, facilitating injury reconstruction and allowing for definitive identification of the weapon used (Fig. 4).

PMCT can visualize injuries in situ and digitally preserve postmortem imaging data in a semi-permanent format. Various visualization techniques have further enhanced the clarity and demonstrative value of PMCT images in forensic investigations. Unlike conventional autopsy images, these images are less visually distressing to laypersons, making them easier to present as evidence in court proceedings, including jury trials, and those conducted under the court-oriented trial system. Furthermore, PMCT can assist in assessing injuries caused by sharp objects by providing detailed information on wound depth, shape, and anatomical trajectory, thereby supporting interpretation of the weapon used [9,10].

In homicides involving sharp-force injuries, PMCT can be used effectively to localize weapon fragments before autopsy and provide critical information for weapon identification. PMCT is useful for the visualization of retained foreign materials, assessment of wound trajectories, and pre-autopsy triage. These findings support the role of PMCT as a valuable adjunct in forensic investigations, particularly for determining the cause and manner of death.