Thrill Killing is the act of committing murder for no reason other than self-satisfaction or to receive either a sexual or emotional "high" - due to the fact Thrill Killers often target complete strangers and have sadistic personalities that involve torturing and dehumanizing their victims as well as the fact they commit extreme crimes for no reason other than personal enjoyment they are the most feared and hated kind of killers.
Thrill Killing has been blamed in modern times on violent media such as video games, access to pornography on the internet and a "modern world of sin" mentality - in reality however the modern world has not seen an increase in Thrill Killing, it is simply being exposed to a larger audience than it was in the past.
Thrill Killing is a classic sign of sociopathic behavior and can also involve the torture and murder of animals, as many Thrill Killer pick targets they believe will not fight back and who can be easily "snuffed out".
Thrill Killers are often stereotyped as vicious teenage males and although this is sadly the truth for many not all Thrill Killers are roaming gangs of young males.
Many Thrill Killers enjoy collecting videos and pictures of their actions and some go as far as releasing them in the hopes of gaining infamy for themselves - although the rise of media sites and video-sharing has once again been blamed for this behavior the practice is much older than the internet (for example Jack the Ripper frequently left notes taunting the police, presumably for thrills - the most infamous of which is the "Letter From Hell").