Theoretical (and probably absurd) Human Biology Question

[MonkeyPundit]

I'm working on a plot device for a piece of creating writing that I'm undertaking, and I wonder if any Human Biology experts could answer a theoretical question for me.

Here's my question: is there any way that an assassin could nefariously turn a white man (literally) black, in terms of his pigmentation? I'm thinking either something to do with Iodine, a virus or a bacteria, or perhaps even DNA of a Gorilla (which, of course, has black skin). The desired end result of this plot device is that the character would have a simian appearance.

Best Regards,
James Clarke

[JackBean]

are you sure gorilla has a black skin?

[jfeather]

Would it be plausible in your story to just dye them, like with the spay on tanning solution only darker?