watch this documentary and answer 4 questions based on it

Please watch this documentary about a very famous serial killer: Son of Sam: https://www.youtube.com/watch?v=sPF3fuICqhM
After watching the video, please answer the following questions in at least 3 sentences each or more:

1) What was the time period and area that he was operating?
2) Why did he commit the crimes?
3) What was his MO, signature, victim profile (common things about his victim or victim type)?
4) What mental illness did he suffer from?