Jackie Vance was the wife of NCIS Director Leon Vance and who, in addition to being a housewife raising their two children, was responsible for killing former North Korean assassin Lee Wuan Kai who her husband had been obsessively chasing around the world for twenty years which occurred in the last few moments in the Season 7 episode Endgame (episode).
She died in the Season 10 episode Shabbat Shalom (episode) and like Eli David, was killed after being hit by machine gunfire although Vance tried to keep her alive while she bled out in the kitchen. Despite his best efforts, Jackie succumbed to her wounds during surgery with NCIS Medical Examiner Dr. Donald Mallard later determining that Jackie had died after being shot in the temporal lobe of her brain.
Jackie was shown to have a loving relationship with her husband. However, in Shabbat Shalom (episode), she was frustrated with him for not spending enough time with her. Leon had promised her that the evening of her death would be a date night for the two of them after she showed up at work to see him. He later angered her when he brought Eli home for dinner to try to help him.
In order to cover up under Presidential orders the reason for Eli David's death, as a means to avoid a conflict brewing up in the Middle East until they discovered who was responsible, Jackie's death was summarily covered up as being the result of a break-in gone awry.
Her death also deeply affected Leon, which eventually resulted in him being put on a temporary leave of absence by SecNav Jarvis after he, in his anger for his wife being killed, angrily confronted a subject and almost exposed prematurely that Eli was killed, thus nearly breaching his orders from the President and the State Department.
At some point between the NCIS bombing and her death, Jackie created a separate bank account so her family could remain financially stable out of fear that her husband might perish on duty. However, she never informed Leon Vance of this, which led to him becoming disturbed at the possibility that he never actually knew his wife as well as he should have, although Gibbs later set him straight.