Pyramid Head sighed when he was asked that question. Technically, as an angel created by his God, he couldn't lie. In fact his entire existence was based around forcing people to see the truth. I talk to many people.
After a minute, Pyramid Head then sent the following the message back. Sam Winchester, Heather Mason, Claire Littleton, Angela Petrelli, Niki Sanders, Elisabeth "Psylocke", Tenel Kal Djo, Kira Ford, Willow Rosenberg, and Alessa Gillespie. All of them are guilty. All of them must be given the retribution they desire.