Catherine then sashays in to drop her lab results in Gil's lap: "Oil-based blue paint mixed with motor oil." The music gets all ominous as Gil decrees, "He's back."
"He" would be the Blue Paint Killer. Let's re-acquaint ourselves with the said killer, as per Season 3's "The Execution of Catherine Willows." I've excerpted all the relevant stuff from the recap for you, thus recapping a recap and plunging us all into a post-modern abyss of self-referentiality. Do you feel like a French deconstructionist yet? Here's what you need to know:
Catherine exposits for all of us: "People v. John Mathers. Serial. Western LVU. I was a rookie." Western LVU is turning into UC Sunnydale with the mortality rate. I wonder if they're in the same athletic conference -- the DEAD 10? Gil recognizes the case -- three dead coeds, all sexually assaulted with no semen found. The women were found dead and bound in garbage bags. Catherine explains, "The strongest evidence was victim #3, Charlene Roth. Mathers, a campus security guard, got murder one for that."
But just before he's executed...
Cut to Catherine catching Gil in the Labitrail and telling him, "A stay. New evidence -- hair analysis. I've already overnighted the six pubic hairs found on the victim to Norfolk Department of Criminal Justice for mitochondrial DNA analysis."
Detective Buzz has called her to Western LVU because "your name's on the memo." Catherine wants to know what memo, and Buzz tells her, "Young female, bound, trash bag. Copycats come out of the woodwork every time there's an execution." Damn, Texas must have its hands full. Come to think of it, so does Virginia; I wonder if the Norfolk Department of Justice lab is open 24/7 to handle all the work. Catherine groans, "Mathers's attorney's going to have a field day."
The attorney's having a better time that the CSIs, who were facing the problem of a killer on the loose instead of being in jail: