Pretty Little Liars Promos: "A Person of Interest"

Was the end of this week's Pretty Little Liars the beginning of serious trouble for one main character?
On "The Bad Seed," evidence against Ian turned into a major problem for the core four, as the hour concluded with Aria, Spencer, Hanna and Emily being taken away by the police. Interrogation awaits next Monday, and the following previews make it clear that at least one Rosewood High School student might become a prime suspect in Alison's murder.