Zac
Zac watched the news unfolding live as he ran on his treadmill, taking great pleasure at the strain and discomfort on Nico Andrews's face as Toni gave her statement to the press. He couldn't have orchestrated it any better; it turned out to be quite the media circus, and from the look of panic on Toni's face, it was just what the doctor ordered.
He had called in specialists to tell him just what he needed to do to make sure Toni didn't regain her memory. If she did, he'd be fucked, and he'd worked too long and too hard for her to swoop in now and take the company away from him.
James was a sly old fox and just before he died, he changed his will to state that if any living relative came forward and could prove he or she was related by blood to him, they would gain complete control of his company and all his holdings. It was almost as if dear old James knew his precious daughter was alive this whole time and was making preparations for her triumphant return.
Zac knew James was keeping something from him, he just had no clue the secret was this big or could destroy everything he had worked so hard to put into place. A part of him always wondered if James knew what really happened to his daughter. If he had known Zac was responsible for Toni's death, he never let on. Not until the very end, when Zac shared that little bit of information with him, just before he pushed James off the pier, killing him. Zac was fortunate enough that the local authorities believed his death was a suicide. The few cops who came snooping around, asking him questions, were easily paid off to take whatever story he wanted to give them. He had escaped all speculation, but now that Toni was back from the dead, she held the key to his downfall in that forgetful little brain of hers. He couldn't sit back and hope that she never regained her memory, that was too risky even for him. Zac needed some reassurance and the only way to get it would be to finish what he started over a year ago when he knocked her unconscious and shoved her lifeless body overboard. This time, he wouldn't fuck up. This time, he'd make sure the job was done right because he'd worked too hard to get to where he was.