why does al kill himself?

He was ashamed that he tried to kill Tris, so he kills himself. They find the body the next morning, and Tris was surprised that it was Al.

Al kills his self because he iis very ashamed of what he did to Tris that night and got very upset when she told him too stay away from him or else she would kill him. After Al dies Tris is very upset and feels very guilty about what she says.