Step into the Abyss

A woman died after falling from the terrace of the twenty-fifth floor of a London bank.
You are arrested for her murder. You explain to the police that you met the victim the night before at a corporate party. She threatened to jump off the roof, but you dissuaded her.
You have nothing to do with this tragedy. You are clearly being framed. So why does the police continue to look for weak spots in your story? Even the lawyer doesn't seem to believe you.
It is already clear to everyone that you are hiding something. But who are you trying to protect? Whose secrets are you keeping? And why?