I tried to recommend some dramas that have crime and mystery mixed in with some romance.
Cruel City - I see it is already in you PTW , I would definitely give it a chance.
One Million Stars Falling From the Sky - The romance aspect takes on a strange twist, but none the less it is a pretty solid crime-mystery mixed in with some romance.
Bad Guy - The plot isn't a very unfamiliar one, but you might enjoy it nonetheless. I saw Innocent Man on your PTW and they are both pretty similar. If you end up enjoy Innocent man (Which I also enjoyed) I would give Bad Guy a shot.
Who are you: School 2015 - I'm usually not very fond of school based dramas (especially if it touches on romance) but this one was enjoyable.
Seijo
Ice World Guilty Akuma to Keiyakushita Onna
Hope you check some of these out and enjoy them!
