Max Ellswood was one of the original researchers on the ANAX Principle, a research project for the military which was later shut down for four decades before being restarted. Ellswood emerged and killed Paul Booth because the Lieutenant was about to reveal the project's existence to the press. He then tried to kill Penelope Langston but was arrested by her grandson, NCIS Special Agent Timothy McGee and McGee's colleagues, fellow NCIS Special Agents Leroy Jethro Gibbs, Anthony DiNozzo and Ziva David.