Character description (or lack of): A question

I've got an odd one for you peeps out there. I mentioned awhile back that I've got a character who is Asian American. While I do some descriptions of her initially, I don't mention this until about the third or fourth time she shows up. I did this specifically because I wanted to avoid the reader filling in any stereotypes before they had a chance to get a grasp of the character.

Ever since then, I've been debating over another, but somewhat similar issue. One of my MCs cohorts is African American. This is mentioned briefly in the first chapter, though nothing is ever really made of it. It does, however, serve a minor purpose in the story. There is a scene when a character is killed and the initial scanner report says that a white male was seen leaving the scene. Now, it's pretty clear early on that my MC had nothing to do with this, but part of the fun of the middle of the book is that my chick is being lied to by an FBI agent about said MC, and one of the things she uses to convince her that he's a bad guy is a sketch from a "witness" testimony that's a dead ringer for his cohort, claiming that he's the one who killed the other character. Uh...hopefully that made sense.

It's a small detail and in theory the reader is on the MCs side, but it's just one of those moments when even though you're on his side, you kind of wonder about this as well. Well, I'd hope anyway. So it's essentially a small detail that should be a clue that they're lying (because the initial reports stated white male), but that she misses.

I've been seriously considering not mentioning at all until this interrogation scene that he's African American. Granted, one of my friends read it and said that he always forgets that, so maybe it's not a big deal in the first place. I tend to like allowing the reader to establish their own idea of what the characters look like. I guess what I'm wanting to know is if you read a character and assumed he was white (the other two are, though honestly I don't know if this is an assumption everyone would make or only white people would make), would you be irritated to find out halfway through the book that he wasn't?

I always think of Atlas Shrugged where she described the main character as blond, I think, and it drove me crazy because in my mind she had jet black hair (might have that backwards), but that was something she mentioned often from early on.

Anyway, just looking for opinions. I don't think it detracts from the story to have it in there early on, but I kinda like the idea of not mentioning it, too.

That's true. I didn't think of it as hiding it, but that's essentially what I'd be doing. Good point. Thanks.