From The TV IV

Officer Ziva David works for the Israeli Mossad intelligence agency, and is the daughter of Mossad Director David. She was Ari Haswari's control officer, and was temporarily tasked to NCIS Headquarters in Washington, DC to stop Special Agent Jethro Gibbs from killing Ari, claiming lack of evidence on Gibbs' part that Ari was actually Special Agent Caitlin Todd's killer. It turned out that Officer David was Ari's half-sister, and, when it became apparent that Ari had really shot Caitlin and was a Hamas agent, Ziva shot him herself. Gibbs and Ziva fudged the incident report, claiming that Gibbs killed Ari himself.

Officer David was later assigned to NCIS to act as a liason officer, and proved herself a more-than-capable field agent on her first mission.

[edit] Trivia

• Ziva David joined the regular cast of NCIS as of 3x04 Silver War.
• Play's Agent Dinozzo's lover on an undercover mission

NCIS Characters

Special Agent Leroy Jethro Gibbs | Special Agent Anthony DiNozzo | Special Agent Timothy McGee | Officer Ziva David Special Agent Caitlin Todd (†) | Abby Sciuto | Dr. Donald "Ducky" Mallard | NCIS Director Jenny Sheppard