Millennium - Season 1 Episode 17 Walkabout

Peter Watts tells Catherine that Frank missed a routine homicide review with Yakima police that morning. Fearing the worst, Peter and Catherine access Frank's computer, looking for clues that would shed light on his disappearance. The pair uncover email correspondence between Frank (using the pseudonym "David Marx") and a Doctor Daniel Miller. Catherine tells Peter that five years ago, just before Frank collapsed, he would sometimes vanish for days at a time and check into hotels using the same pseudonym.