"Tell Mike it was only business. I always liked him."
He liked him so much that he betrayed him.
Salvatore Tessio was one of Don Vito Corleone's most trusted friends and also his Caporegime.
In the game, Tessio is executed by Aldo Trapani, after, when arriving at the Embassy Club, he attempted to escape. His final words were: 'It's just business I tell you. Only business.'