From pilot episode.
Geils follows Tribeca to the hotel where the Mayor's fundraiser is being held in episode 2x10 "Electoral Dysfunction".
Atkins' brother Eric uncovers a buried clue in front of the observatory and is promptly murdered in episode 4x09 "Irrational Treasures".
Angie and A.J. wake up in the ruins of Air Force Two where they have one final confrontation with Vice President Perry in episode 4x09 "Irrational Treasures".