"Flash Pop" is the 14th episode of Season 8 and the 176th overall. It originally aired March 30, 2012.
One of the lab techs is murdered in much the same manner as the victim in a cold case from 1957, and the perp sends photos of the scene to Mac and Jo's personal phones. Christine invites Mac to her parents' 50th wedding anniversary party and the two begin to show a romantic interest in each other.
Tropes for the episode:
- Awkward Kiss: Downplayed. Mac kisses Christine on the cheek at the party and she responds by kissing him on the lips. She's a little embarrassed at herself, but it's still romantic.
- Due to the Dead: The lab techs hold a simple, quiet vigil for the young woman who was killed. Jo is particularly moved by this.
- Monochrome Past: Scenes from 1957 are shown in muted colors with a Film Noir-ish feel.