Violence is a characteristic in the Slasher Genre that allows the audience to see gruesome killings with extreme detail within the safety of their own homes.
Violence is often used against sexually active teenagers in an isolated location away from any source of help. This educates the audience that if your a teenager and have sex you will get killed. By isolating the teenagers it will cut off any hope of survival.
In the movie "Halloween" 1978 by John Carpenter the violence was very low compared to modern slasher films. This image is an example of the first killing where a girl gets strangled in her car.
Violence continued to evolve as seen in the movie "Friday the 13th" made in 1980 by Sean A Cunningham. This scene involved an arrow going through the neck of a teenage boy after having sex.