Furious finale explained by Liz Meriwether, Emmy Rossum, and Lola Petticrew

With episode 8, Furious closed the case on the vengeance-seeking serial killer named Catherine (Lola Petticrew).

But with that final scene, FBI Agent Alice Black (Emmy Rossum) unlocks a new mystery that might be pursued in a second season.

Where could that lead? Mashable Entertainment Editor Kristy Puchko sat down with Furious creator Elizabeth Meriwether and stars Emmy Rossum and Lola Petticrew to dig into finale burning questions and what could be ahead for Season 2.

Obviously, spoilers from "Hart Island" ahead.

Who killed Isabel on Furious ? Lola Petticrew and Emmy Rossum star in "Furious." Credit: Disney / Sarah Shatz With the trauma of being trapped and sexually assaulted in a child trafficking ring, Catherine has been fighting all season to remember what exactly happened the night Isabel died.

In the final episode of the season, she goes back to where it all went down, the posh mansion of Jay Easton (Peter McRobbie).

There, an ailing Jay relies on his daughter Emma (Hope Davis) to clean up his mess.

In this case — with cops, Feds, and Catherine incoming — that means destroying any evidence, including Jay's treasured collection of child porn.

While Catherine killed the pimp who trafficked her, Jay's son who was there that night, and two of the family's lawyers, she does not kill Jay.

But in searching for the truth, she realizes that it was she who killed Isabel.

In a tearful scene with Emma, Catherine realizes that Isabel was bleeding, possibly from postpartum complications but also because Jay beat her in the face.

Crying out in pain, she asked Catherine for help.

And Catherine administered a deadly dose of intravenous drugs to euthanize her first love.

So, Catherine killed Isabel, but out of love.