I found out that los raizales are Colombians that live on San Andres, and nearby islands. From what I've read so far on the history, they are descendents of African slaves and the indigenous people who inhabited the island. In a sense, they are afro-colombiano, having darker features because of their African ancestry. It's pretty interesting to read about current issues with San Andres. It looks like a beautiful region, but there seems to be a political tug of war between Colombia and Nicaragua about "ownership" of the island. The Raizales believe that it is theirs, and they would like independence from Colombia. Here is an article from La Prensa:
LA PRENSA - Nacionales
It's in Spanish, but an interesting article.