Psychology Asspect

I am currently in a psychology class and we touched on the topic of serial killers for a brief minute. Their home lives may have not of been the best. Such as they may have been beaten, parents may have been addicted to drugs alcohol or both, or they may have even been raped as a child. That doesn't mean that every child exposed to the occurrences will be a serial killer. With that being said, it also means that not all serial killers have this as a background in their childhood or even their lifetime. I find it so intriguing on what actually runs through their mind, what their childhood was like to make them just go on rampages on just kill, even innocent people.