Most are man-made and fall under the domestic violence community. This could be the case of a husband killing his wife, girlfriend or lover. In contrast, suicides represent a smaller fraction of homicides overall. Regardless, they differ significantly from domestic crimes. In such cases, depression appears to play an important role, with 17 out of 18 authors diagnosing major depression or some form of mental illness. Some studies have shown that a majority of killers abuse alcohol or drugs. It can be said that these murders are mostly impulsive and are committed in a stage of rage or jealousy made possible mainly by the presence of a firearm nearby. Contrary to this, mass murderers plan their crimes carefully, they wait for the right opportunity to present themselves or act. In this case, they involve many innocent people in their