Sawyer was Liberian/American.
Yes, that is why it was obvious who Isaacs’ was referring to in his testimony. He did not use his name.
IIRC he was traveling with his US passport. Which explains partly the kid gloves treatment he got and the lack of ‘care’ used by the Nigerian medicos. They didn’t initially know he’d come from Liberia much less had held his sister who was dying of Ebola. And to quote one of the Nigerian ministers ‘he was quite economical with the truth’.