The Chambers of Scerets is open, from the accident of Harry talking to the snake and order to attack Justin. Everyone now not at the Harry side, also Ernie.

"Hannah, he's a Parselmouth. Everyone knows that's the mark of a Dark wizard. Have you ever heard of a decent one who could talk to snakes? They called Slytherin himself Serpent-tongue."

Ernie talking to Hannah about his suspection on Harry is the heir of Salazar Slytherin. You also there, hearing everything...