2x13 The Mikado, written by Michael R. Perry, Erin Maher and Kay Reindl, directed by Rod Pridy.
Teen boys searching for online porn (the lost music of dial-up modems!) encounter a live snuff show. When the the view counter reaches a specific value the victim is murdered.
The same setup was used in the later film Untraceable (2008). The internet finds no known crossover with this episode, although fans pointed out the similarity at the time.
Frank, Peter and hacker Roedecker are on the case, the latter over the moon when he gets to use the Millennium Group's computer facility, deluxe and deserted.
Frank believes the killer is a police-taunting psycho from an earlier decade. His code name is "Avatar" and he is suggested by the Zodiac killer who was never identified.
Everyone who ghoulishly views the site takes the victim closer to death, a sad reflection on the human condition. Of course, the investigators are doing the same thing with a better purpose.
Roedecker is proud to show off his talents until they get too deep into the case and then he doesn't want to see anymore.
quote
Roedecker: Some people feel liberated from their normal self when they adopt an internet persona. In the anonymity of cyberspace people are free to experiment. Online I've changed my name, my appearance, sexual orientation, even gender.
Peter: That's more personal information than I need, Brian.
Avatar escapes but Frank knows he will return when he has another evil gimmick. I don't remember that happening in the series.
Notes:
The title is the killer's favorite opera, featuring "The Lord High Executioner". It's supposed to be a comedy.
Frank complains that his gift doesn't work remotely. He has to revert to a more traditional identification with the killer.
Is Roedecker playing with his Christmas gift?
The ip addresses shown are out of range, typical for TV and movies. Either they don't know or are careful not to use a real address.
They don't use the word but we see the killer using steganography, taunting the police with clues hidden in his images. In this case a WAV file; not very efficient.