Why did I finished Carnal Sins and the concerned citizen's sermon still can be found in Novigrad?

[π]

Isn't that lunatic higher vampire?

[deidian]

Supposedly yes, it is the higher vampire.... When you mistake Nathaniel for the murderer and bite the bait the quest log will tell that later more assassinations following the same motive where committed, so Geralt didn't caught the assassin, but Dandelion will be pleased cause his friend didn't let him down.

If you go ahead till you catch the vampire quest log will tell solved, assassin caught by Geralt.

[Furiey]

It's a bug. They continue to appear even after you catch the correct killer (the vampire).