Anyway, Catherine ha-ha's Sara's crunchy sensibilities and notices that Sara's been testing for gunshot residue, which she's found. Sara tells us she was testing Todd's jacket. Catherine adds, "So it means he may have fired the revolver you and Grissom found in the park." I love how Catherine always waltzes in on her day off or her court date and advances the case in passing. Sara replies, "Yeah. Too bad GSR testing can't tie a vic to a particular gun." Ah, but maybe Gil can. Who can take the GSR, and tie it to a vic? Who can take the evidence and solve crimes really quick? The Grissom Man can, 'cause he knows a lot of things, and breaks the case open wide. Catherine tells Sara that Gil's down in Ballistics, "meditating over your revolver. He didn't even look up." Sara gets a wide grin and gasps, "Excuse me," before running off. As she passes Catherine, the older woman smiles slightly.
Sara charges into Ballistics, where Gil is peering intently into a scope. She chides him, "You could have waited for me." This sails over Gil's head. He gestures for her to check out what he's seeing in the scope. It's burnt skin. Gil theorizes, "I think someone palmed the cylinder gap." For those of us not intimately acquainted with gun parts, it means they cupped their hand over the barrel, for reasons known only to them. We see the firing and the burning via TMICam. Sara says, "Todd Branson had GSR on his jacket. If we could get his DNA off this revolver, we could tie him to this." Gil pooh-poohs the idea: "Burnt skin is useless for DNA." Sara's got him on this one: "What about sweat? There's a seventeen-percent chance of DNA recovery from a shooter's perspiration." This is news to Gil: "Seventeen percent?" Sara's in her glory here: "Yeah. New paper out of Australia. You haven't seen it? Seventeen percent chance of DNA recovery from the grip of a gun, sixty-seven percent chance from a cigarette, thirty-two percent chance from the brim of a hat. [pause] Would you like a copy?" Gil pretends to mull this, then says, "I don't need one. I have you." Hee! I love it when Sara's coworkers tweak her over her stat-supported geekery. Gil then instructs Sara to swab the pistol grip and get it to DNA. She just stands there, puzzling whether Gil's teasing her about her stat-spouting like Warrick and Nicky, or if he's hinting at something else. She eventually settles for deciding -- wordlessly -- that Gil's being his usual opaque self.