What people thought about Trayvon Martin's Death?

Many people believe and say that Zimmerman killed Trayvon because of racial issues, others say because he was in possession of a gun when he encountered Trayvon he felt powerful. While i was doing some research i saw a video of Bill Cosby. In this video he strongly believed that it was not a racial issue but a gun issue. On the other hand people say because he was a black kid on a white neighborhood with a hoodie he looked suspicious and up to no good and seem like a threat so he shot him.