There are two main types of aggression, active and passive. Violence is active aggression. Aggression may be expressive, designed to draw attention to oneself or to make victims suffer for the sake of suffering, or instrumental, committed for personal gain. Aggression is the source of violence, although not all aggression is violence. There are many possible sources of violent crime. Physical sources stem from human biological or psychological processes and include mental disorders, substance abuse, and evolutionary factors (sociobiology). Social and cultural sources of violent crime include family dysfunction, social disorganization, and some subcultural values.
The four violent offenses recognized by the FBI’s Uniform Crime Reporting program are murder and non-negligent manslaughter, rape, robbery, and aggravated assault. Murder/non-negligent manslaughter is the willful killing of one human being by another. Homicide is the killing of one human being by another, regardless of intent; all murders and manslaughters are homicides but not all homicides are murders. Manslaughter is an unlawful homicide committed without premeditation. Most states recognize at least two degrees of murder, first and second; some also recognize a third degree and/or a crime of felony murder. Mass murder involves the killing of three or more people in a single incident. Serial murder is the killing of several victims over a long time with relatively long periods between each killing. Such offenses are relatively rare. No single factor causes someone to become a serial murderer, but a significant factor may be the offender’s personal decision in choosing to pursue his or her crimes.
The FBI's definition of rape is: “penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim.” Traditionally, the offense applied only to female victims, but most states now have gender-neutral definitions. The three general elements of the crime are sexual intercourse, force, and the victim’s lack of consent. The two main types of rape are stranger rape and acquaintance rape. Knight and Prentky have devised a four-category typology of rapists that includes anger rapists, power rapists, sadistic rapists, and opportunistic rapists. There is no single cause for rape. There are several rape myths, which are more commonly accepted by males than females and that affect reporting, prosecution, and punishment. Rape is also associated with a number of male fraternal groups, such as the military, college fraternities, gangs, and sports teams. Rape in prison is also a controversial topic; the 2003 Prison Rape Elimination Act is an attempt to control the problem.
Robbery is the taking or attempting to take anything of value from another person by force or threat of force or violence, or by putting the victim in fear. Some of the more common types of robbery include street robbery, convenience store robbery, and bank robbery. The motivation is generally the need for money.
Assault is an attempt to inflict immediate bodily harm upon another person or making that person fear harm is imminent. Battery is the illegal use of force against another person. Essentially, assault is an attempted battery, and a battery is a successful assault. Many assaults are committed solely for the sake of harming another person, or making that person afraid. These include stranger assaults, intimate partner violence, and child abuse.