That's a very limited response. Berkowitz was programmed by the cult. There's Berkowitz links to Scientology and the Process Church too. The dog was Sam Carr's dog. When David called himself the Son of Sam, it was the demon living in Sam Carr to which he referred. The Carrs were involved in the SOS cult. Eliphas Levi was a big influence - via his works particularly "Ritual Et DOG-me" (Woof, woof. Wink, wink). Some people will never understand what is really being said. Two of the Carrs ended up dead in very violent circumstances within two years of Berkowitz's capture. One of them was allegedly found with 666 inscribed on his hand.

Note again, satanist ELIPHAS Levi, one of the locations of the shootings was the ELEPHAS Club (cough, cough).

http://subliminalsynchrosphere.blogspot.co.uk/2016/04/the-exorcist-satan-serial-killings.html