Ghost
유령 (original)
The police procedural tackles crimes and clues in the cyber world, weaving a massive, twist-filled mystery of murders, identity switches, corruption and conspiracy.
Starring So Ji-sub, Lee Yeon-hee, Uhm Ki-joon, Kwak Do-won, Song Ha-yoon, Daniel Choi, Kwon Hae-hyo, Choi Jung-woo, Jang Hyun-sung, Jung Dong-hwan
Watch "Ghost" on Rakuten Viki released in 2012. It's a crime and mystery show, and has a rating of 7.8 out of 10 from Imdb which is usually fine for this kind of show, and is currently available to watch for free.