Wait, why do you say he did the killing on Valentine's Day? Is it because Vernon was with Sal Maroni and told him Harvey thinks Maroni is behind this Holiday thing? The fact that the heart-shaped box of chocolates Holiday left at the scene is identical to the one Harvey gave Gilda? Or the fact that Harvey came home late that night to his wife? I do see why you say Harvey. The only reason why I was thinking of it being Alberto is because the fact that the target of the killing was Maroni's men.