Patrick Dempsey.Jan Thijs/FOX Tap Here To Add Us Weekly As A Trusted Source Add as a preferred source on Google Memory of a Killer premiered in January with Patrick Dempsey embodying one of his most complex roles to date. But who does he play on the Fox series? Dempsey portrays lead character Angelo Doyle/Flannery, who is "leading a dangerous double life while hiding an even deadlier person secret - he has developed early onset Alzheimer's," according to a Fox press release issued in July 2025.