Arthur Janson was a businessman who lost his sister, Rebecca to a UAF attack and later formed a partnership with Hamzi Khan who was married to Rebecca to get revenge for her death.
The two were successful in recruiting Yousef Kaleem to steal the missile for them but OSP who had gotten involved with the case were hot on their trail.
The two Agents attempted to get Janson to surrender but he refused, instead choosing to release a drone from the stolen missile, forcing Callen to shoot Janson in the right arm.
Jenson was eventually arrested and presumably jailed for the planned terrorist attack.
- Andrew Borba previously appeared in the original NCIS series in the Season 6 episode, Toxic (episode).