Desiree's Baby

There were two main twists in the short story "Desiree's Baby". The first is when we find out that Desiree's baby is black, leading Armand to believe that Desiree is black. I had no idea that the story was heading in this direction until the point in the story when Desiree starts to panic and falls to the floor crying. The next twist was the very end when Armand reads the letter from his mother to his father revealing that Armand's mother was black. This was also shocking to me but not quite as shocking because he was described earlier in the text as having dark skin. This to me was a bit of foreshadowing that alluded to his secret heritage. The question I have is are both Desiree and Armand of African American decent or just Armand?