In Pretty Little Liars Season 2 Summer Finale:What was Jenna and Garret talking about?(For those who haven't seen the finale, this could be a spoiler..)

In the scene where Jenna came to the police station..What where they talking about? Did they kill Alison? Where they the ones who set the girls up? They seemed so happy about what's happening to the girls. And it was Garrett who چرا لیا, چوری کی page 5 of the autopsy رپورٹ so they could get rid of the evidence linking them to the crime? It wasn't کہا if they were really "A." But it seems to be implied that they are....
And oh! when they mentioned Jason, they کہا Jason figured out that it wasn't him who killed Ally, then what was the اگلے line that they said???
I'm just so confused!!!