3XK earned his monicker after killing three women in a single week, disappearing for month, only to return to kill three more women. Brutal!
How did 3XK kill his victims?
He strangled them with a rope, natch. Creepy fact: All of 3XK's victims are blond and after he killed them, he'd pose them lying down with their arms crossed across their chests, as if they were lying in coffins.
How did he make his comeback?
Well, cue disappearing act number two and fast foward four years. The team figures out 3XK is back after they find two strangled blond victims,. They work to stop him before he gets to his third, but end up getting outsmarted by the murdered.
What's 3XK's psychological profile?
According to Castle, the guy's got some major mommy issues. He was an unwanted child from a single-parent household and his mother died when he was just 12-years-old. From there he went from bad foster home to bad foster home.
Why does he return in Castle Season 5?
He confronts Castle while Castle is trapped in an isolated cell (Castle ended up in jail for Tessa's murder) and admits he's back to avenge Castle for ruining his vanishing act so that the cops would stop looking for him and he could "begin killing again... taste that fear again." Instead of killing Castle, he wants to destroy him, which is why he came up with an elaborate plan to frame Castle for Tessa's murder. And then 3XK is going to have his people murder Castle in central holding... or so he threatens! Castle staged a fake transfer to central holding through some connections and used his freedom to pin down Tyson with some solid evidence (which included a casting magazine ad, a bogus check, and a lookalike among other things). The evidence gets Castle's murder charges drop, but the drama with 3XK is so not over. The murderer ambushes Castle and Beckett on a bridge, where Castle ends up shooting Tyson and Tyson falls off the bridge. Tyson's body isn't found the next morning, and Castle assumes this was all part of his elaborate plan to disappear so he can start killing again, "How does a wanted man stop being wanted? It has to be public and it has to be final."
Notable quotable: "People think it's killing that I like, but murder's just an act. It's all about the anticipation, the planning... "