What is the point of the Koreatown Killer subplot?

Question

In the TV series Bosch, the Koreatown Killer ("KTK") is bicycle-riding serial killer who chooses his victims apparently randomly, usually also taking their cell phones.

He first appears in S3E1, appearing sporadically and usually very briefly. His last appearance is

in the middle of S4, when he meets his death in a traffic accident that seems to be completely unconnected with his killings.

The police investigation gets very little attention from the show, but

Crate & Barrel do connect the dots -- after his death -- and determine that this dead guy used to be KTK.

I don't understand why this subplot exists. We never learn much about KTK, or why he kills. We spend very little time with police who are trying to catch him. Perhaps I'm forgetting something, but I don't think the show uses KTK's brief vignettes as opportunities to comment on other events that take up the show's main focus.

KTK comes and goes without any ceremony, and has really no impact on the characters and events at the center of the show.

What is the purpose of the KTK subplot? Why did they film it and give it screen time? They carry it on long enough that it seems like a deliberate choice.

Answer 1

It is a plot device

The Koreatown killer is a plot device through which Chief Irving meets Jun Park, his eventual love interest, wife, and mother to his second child. He meets her while visiting the family of a KTK victim, she is there as a community outreach liaison to break the terrible news to them.

The subplot adds verisimilitude

During the various seasons, Bosch is usually focused on a single major case, but they intersperse smaller cases into the action so that the audience gets a sense of what it is really like on the force when detectives have to multitask, shift gears, and juggle cases. Other examples would be the case where there is an officer-involved shooting causing protests that get violent. Another from Bosch legacy would be the rapist case that runs alongside the case of the fugitive and his girlfriend being shot and the case Bosch is working as a PI. The Koreatown killer serves the purpose to create verisimilitude--the appearance of a real city police precinct and all the things they deal with. It also is a way of showing the audience that sometimes in the police business, you just get lucky.

Answer 2

Basically, it's there to show that random violence happens and that sometimes "solving the case" can be just a matter of sheer coincidence and some logical thinking on the part of the detectives.

In general Crate and Barrel are the comedy turn in Bosch but they are also depicted as being dedicated and intelligent offices quite capable of solving these types of crimes.

Does it matter to the overall plot, no, but it adds flavor to the series and the characterizations in play.