David Berkowitz seemed to be troubled from a very young age. Then, after finding out he had been adopted, the loss of his adoptive mother and finding out the details of his birth, something in him snapped. 

Music from https://filmmusic.io:

"Dark Standoff" " "Immersed" "Leaving Home" by Kevin MacLeod (https://incompetech.com)

Licence: CC BY (http://creativecommons.org/licenses/by/4.0/)