Penelope is the girl at the far right in the picture. She is the FBI's Technical Analyst and very good in her character. In fact, in Criminal Minds: Suspect Behavior , she retained her role. If you haven't seen this show, I highly recommend that you watch it.
L-R Characters: Dr. Spencer Reid, Emily Prentiss, Derek Morgan, Aaron Hotchner, David Rossi, Jennifer "JJ" Jareau, Penelope Garcia.