Although psychological gratification is the usual motive for serial killing, and most serial killings involve sexual contact with the victim,[5] the FBI states that the motives of serial killers can include anger, thrill-seeking, financial gain, and attention seeking.[6] The murders may be attempted or completed in a similar fashion. The victims may have something in common, for example, demographic profile, appearance, gender or race.[1] A serial killer is neither a mass murderer, nor a spree killer, although there may be conceptual overlaps between serial killers and spree killers.