Who is Laurence Sobek/Curtis Wood from L.A. Requiem and what is their importance?

Laurence Sobek is the serial killer, who is murdering the witnesses who helped to incarcerate Lennie DeVille. His loyalty to DeVille stems from his own abusive home life. He blames Wozniak and Pike, as well as many other people like Karen Garcia, who once complains that DeVille is photographing children at the nursery where she works, for DeVille's death in prison. He goes undercover as a civilian employee of Parker Center named Curtis Wood, and spends his time outside of work making himself resemble Joe Pike as much as possible.