Serial killers tend to be White males between the ages of 20 and 40, and most begin their criminal careers with petty crimes. Some typical early crimes by serial killers are the torturing of animals and arson. Serial killers frequently have low self-esteem, complicated by some type of sexual dysfunction. Many were themselves victims of sexual abuse and/or were raised in violent households. They tend to be introverted and friendless and may maintain unhealthy ties to a family member, often the mother. In nearly all the murders committed by serial killers, they are motivated by obsessive deviant sexual desires and fantasies. The critical feature of serial killers that distinguishes them from others who may harbor deviant sexual fantasies is that their imaginary scenarios must be translated into the world of real people, who become their victims. Although serial killers may seek ongoing satisfaction by replaying the scenario of a killing in their minds, sometimes using "trophies" and symbols from the victim, this eventually fuels the drive toward another killing. Serial killers generally select victims based on certain physical and/or personal characteristics that fit their fantasy victim. Still, a high priority is given to vulnerable and accessible victims. Although acting under a compulsion, serial killers are cautious in the commission of their crimes, such that there are typically no witnesses and few clues at the crime scene. In the course of committing their murders, victims become objects in a drama designed to fulfill the fantasies of the killer. This means that the serial killer has no sensitivity to or feeling for the victim.