Goth - Vol. 1 Ch. 3

[MangaDex]

 

[Weezer]

the ending is a little unclear here, but in the book

Spoiler

the killer decides to turn himself in, but the MC tells him to wait a few months and pretend like the boyfriend was also his victim. as it turns out, the boyfriend is now buried in the coffin. the MC tells the killer that this is what he wanted, to die with his gf, but he could be lying.

 

[mrboko1234]

@Weezer thanks for the explanation, it was very unclear, this manga is kinda hard to read sometimes because of how its written and laid out