Looking for manhwa

This manhwa involves a "mysterious" string of murders and the MC (i think) moves or someone moves near him during this period. The neighbor is a handsome man, but his nails are always dirty as if he's been digging through dirt.

Sorry if the explanation is bad, I never read it and I plan to and I forgot the title, artist, author.....

Anyways, its a BL where I think the ML and his neighbor are somehow involved with the serial murders going around.