CNN  —  It was June 2021 when my phone first rang with a call from a Russian number. I was working from home, seated at my dining room table in the middle of the afternoon, and suspected it was spam. Instead, it was Paul Whelan. That phone call was the first of a dozen I would receive from the detained American as he spent more than five years in Russian detention before his release in July as part of a historic prisoner swap. I also received four handwritten letters. When I began to cover