The fact that the man knew his name came as a shock, but if he had been here before and they had met, then there was always the chance that he had introduced himself... however, it was when he continued talking that Spencer became more interested, and his thin jaw slowly started to drop open.
When he mentioned Diana, though, Reid froze in horror. His mouth dropped completely open and his eyes stared, wide and terrified. How... h-how did he know that...?! How did he know he wrote to her?! How did he know her name?! And then, his most terrifying, crazy thought of all: Diana forgave him? If that was true, then...
"How... how did you know...?" he asked, in complete shock, but he almost wanted to ask more... not that, you know, scientifically any of this could really be happening. The chances of the Management having done background work on him was more likely, more plausible, though there were recorded cases of people having a 'third eye' and making some rather convincing calls...