Expedition: general discussions.

My players haven’t figured it out yet that their kindly old NPC quest-giving wizard is actually the big bad of this story arc.

See, the heroes with all good alignments have a bounty on their heads for doing a good deed the local king didn’t like because it interfered with his plans. The wizard took advantage of this.

I keep sending them on missions. At first, the wizard did send them out against bad guys, but the quests he’s been giving them have been progressively morally suspect.

I might have to start changing alignments soon. I thought after they robbed a bank and terrified everyone inside that they would start to question the motives of the wizard. NPCs on the street run as soon as they see them.

I've given them so many hints that this guy isn't what he seems. They literally do whatever he tells them to even if there's nothing in it for them. Another npc told them he is evil multiple times and they didn't believe it.

How do I get them to realize there's something up with this guy? They didn't mind when he disappeared for 3 days randomly, mysteriously knew to hide all their belongings when the Watch raided their base, and stole a magic item with a flimsy excuse. They just trust this guy.

Do I continue to try, or let the betrayal be a complete surprise?

Edit: the party is all evil to begin with and has no issues doing terrible shit for no reason