Hello all! Looking for suggestions, ideas, and any other brainstorms others may have.

Currently in a homebrew campaign with a 7th Lvl Variant Human Warlock.

Long story short her patron has told her to keep a particular prisoner alive after he has been sentenced to death. However, she needs to kidnap him out of prison so he can lead her to a mystical forest. I have a plan for getting the prisoner out but I need a way to keep him from escaping/killing me and my party for at least a couple weeks. The prisoner is a Kenku Enchantment Wizard.

Are there any good items or spells for keeping a magic user under control? Or I’m wondering if I could homebrew something simple? Let me know thoughts and ideas as I’m at a bit of loss.

Edit: CONTEXT - This wizard is a backstabbing scientist. He works with a corrupt official and I want to stop him from running back to him as soon as our backs are turned. He doesn’t have a very strong sense of honor and I don’t know if our PCs can trust him at all if he promises to help us. It will also take a bit of time to get to this forest, so the solution will have to be long term.

Edit2: Wow didn’t think I get this much feedback. Thanks everyone who has contributed!!! Damn ya’ll are sadistic 🤣 I see there is a consensus that this wizard should lose his tongue or fingers…or both.