Chief Aaron Hotchner, and later Emily Prentiss. The team included Jason Gideon, the founder of the BAU, who was known as the best profiler in the Bureau; Derek Morgan, an ex-Chicago Police officer who is an expert on obsessional crimes; Spencer Reid, an expert on geographic profiling; Jennifer Jareau (JJ), the team's communications liaison, who later becomes a profiler and David Rossi, one of the original BAU agents who is also an expert in criminal profiling