We report an unusual case of suicide committed with a speargun shot through the mouth, causing a penetrating brain injury. The special features of the present case are not only related to the method chosen for the purpose but also to the difficulties encountered in confirming the diagnosis. Although this type of suicide has been previously reported, this case is particularly interesting in terms of the shooting mechanism and manner of death. Because of the length of the weapon, which was apparently used and found at the scene, a suicidal manner of death first seemed unlikely and the possibility of a simulated suicide was raised. It seemed impossible for the decedent to have shot himself without a mechanism to launch the shaft through the mouth. However, a complete forensic approach eventually allowed for a plausible mechanism of self-infliction, confirming the suicide diagnosis.