NCIS Season 4 Episode 16

Young Navy lieutenant Roy Sanders, who works on Mark Sadowski's team on International Atomic Energy Agency missions, asks NCIS to investigate 'his murder', having being radioactively poisoned. He keeps getting worse while the radiation source is hard to identify. Ziva works out she knows Roy from a common jogging trail, and falls for the hunky gentleman's charms. His colleagues are the only logical suspects.