Crime/thriller kdramas pref with no romance/have serial killer and diff cases each ep like Voice

Can someone pls give me recommendations 

The Good Detective (2021)

• Signal
• Tell me what you saw
• Tunnel
• The Guest
• Memorist
• Gap Dong
• Hello

 Czakhareina:

• Signal
• Tunnel
• Stranger
• Tell Me What You Saw
• Less Than Evil
• Special affairs team: TEN
• Reset
• God's Quiz
• Partners for Justice
• Vampire Prosecutor
• Sign
• Ghost

All done aside from the last six i checked it out but it looks too old i did try partners for justice, that one i dropped i dnt like the FL 

Cold Case (Japanese) is exactly what you're looking for and it's amazing. I recommend watching the original American version if you haven't seen it yet, it's a great series.

+1 Stranger although it's not a different story every episode 

(the fact that there are people out there who don't want romance all the time makes me happy)

Everyone has mentioned good dramas so i'll Recommend

Team Bulldog: Off-duty Investigation  its a mix between comedy and Thriller/crime There is a different case Every 2 episodes
(: 

• Missing Noir M
• Train
• Mr Brain
• Miss Ma Nemesis