Firstly, this discussion hasn't been made purely because they are the same race, that's a factor, but this isn't purely built off that.
This hypothesis doesn't have much evidence to back it up, but it's a possibility.
Vince has a brother.
Vince's brother is younger than him, Vince is in his mid-30's, where as Matthew is in his 20's-30's
They're both the same race.
They're both in the same general area.
Any other information can be posted in the comments, I'd like to read it.
Thanks for reading this small hypothesis.