Evan Davidson was a Petty Officer in the United States Navy and also a killer who was murdered by One Club owner, Scott Pell when Davidson attempted to kill Lisa Delgado by forcing her to drink poison. Pell saved Delgado and forced Davidson to drink his own poison, killing the Petty Officer before dumping his body in an abandoned restaurant. After a couple discovered Davidson's body, NCIS were called to investigate and formed a temporary partnership with Metro Police Department to help arrest Davidson's killer, not realizing that Davidson himself had been a serial killer.