16. House of Cards

A desperate Rachel and the VCTF team cast about wildly to quickly form a profile of an anonymous sniper who's perched atop the pump house of a dam with a commanding view of his victims in an adjoining park, but their options are limited out of fear that the shooter may have wired explosives that could inundate downtown Atlanta. While the body count rises, John risks his life to save some trapped patrons and Rachel suspects the murderer might be an enraged husband whose philandering wife (guest star Saxon Trainor) is pinned down with her lover.