Sonny Corleone was killed, and the Don Corleone and Tom Hangan Brought his body himself to Amerigo Bonasera because Amerigo owes the Don from the start of the book when Amerigo kid got her ass beat so he owes the Don so he will do it. All his doing is fixing up Sonny face for Sonny mother. Amerigo Bonasera is very upset with this favorite he owes the Don because he knows if he does this he might get killed by the other familys.
Sonny Corleone was upset that his baby sister was hurt and kept getting hurt by Carlo Rizzi, so he got piss off and left his protecion to go see Connie and to handle some business with Carlo, he left and went to the toll booth to call Connie, when he was there he got ambashed by one of the familys he knew he was going to die and he couldit do anything..... Sonny Corleone was now dead, when his bodyguards caught up to him at the toll booth they called and Tom pick up and told him the news. He knew he couldit tell Mama Corleone and had to the the Don but first he called Connie to talk to Carlo Rizzi he told Carlo to come stay at the mall and to be more respectful towards Connie till the baby is born and Carlo knew he was close to death.