Star Trek: Voyager - Season 2 Episode 16 -

Tuvok investigates the murder of a Voyager engineer. Former Maquis and Betazoid Lon Suder confesses to the murder and offers no explanation or signs of remorse. Tuvok, curious to find a reason for Suder's madness, performs a mind-meld on the killer, only to find himself losing his usual Vulcan control and regressing into madness.