Why were the Jews accused of killing Jesus Christ?

I am no religious expert, but I believe the reason is because Jesus was betrayed by someone close to him, who was Jewish. Of course, I believe everyone that was close to him was Jewish. So it's kind like me saying "the Mexicans are out to get me" because there's a guy named Hector who is Mexican and is out to get me. Any time you say the (insert large group here) did something because of the actions of a few you are way off base.