The relationship was nicknamed GSR by fans, short for "Grissom Sara Romance". This is a pun on the CSI abbreviation, "Gun Shot Residue". In a May 25, 2006 interview with the Chicago Tribune, the show's executive producer Carol Mendelsohn indicated that the relationship between Grissom and Sara is "not so new" and they have been a couple for some time.
In the sixth season finale, it is revealed that they are in a relationship, which stirred up great debate among fans. The final scene of the episode showed Grissom reclining on a bed, talking about how he would prefer to die. He says he would rather die of cancer so he would have time to say goodbye to his loved ones. Sara comes out of the bathroom in a bathrobe, and says, "I'm not ready to say goodbye."
Grissom and Sara continue to be involved, but have been trying to keep their relationship secret from their co-workers at the lab. However, in the season premiere episode co-worker Warrick Brown paid some note when Grissom delivered a veggie burger to Sara, who was working late on a case, but neglected to bring him dinner as well. In the following episode, Conrad Ecklie commented that "of course" Sara would agree with Grissom instead of him, which made Sara and Grissom worry for a moment that he might have caught on to the relationship. They are also still learning about one another. In Double Cross, Sara discussed religious beliefs with Grissom while they investigated a murder in a Roman Catholic church. She is agnostic, while Grissom is a lapsed Catholic who still believes in God. When she asks if she has offended him with her opinions, Grissom replies "No, dear." Also, once Grissom started to complain to Greg about loud music, but then Sara says that she turned the volume up and Grissom immediately changed the subject. In the season finale, Sara is abducted by the Miniature Killer, and Grissom realize that this crime is personal. Feeling cornered, Grissom says that Natalie holds him personally responsible for taking Ernie Dell, the only person she ever truly loved,
Sara shows signs of frustration with her long-distance marriage to Grissom, avoiding his phone calls. Later in episode Forget Me Not, when Sara becomes a suspect in a murder investigation - where she's been framed, she reveals to the CSI team that she and Grissom have split up.