A murderer is someone who terminates the life of another person unlawfully. There are numerous types of murderers. Some murder for money. There are some killers who are mentally sick and their act of murder is the result of their psychological problem. There are some murderers who commit this crime in a fit of passion. Religious blindness can also be a cause of murder. There are many instances where a single person has committed a series of murders. This type of killers is known as serial killers. Generally, they murder strangers and they do it just for the sake of killing. Mass murderers are those who intentionally murder a large number of people either at the same time or over a short period of time. Spree killers are those who commit the act of murder in several locations within a brief period. Often a family member intentionally murders a particular person to protect the honour of his family. This type of murder is called honour killing. Research says that certain conditions like negligence and abuse in childhood lead persons towards criminal activities. This section provides information about s infamous murderers from all over the world.