Tony to try to pursue a relationship with Ziva. NCIS Director Jenny Shepard In the fourth season, Tony's relationship with Jenny Shepard is shown to have warmed considerably in comparison to the end of the third season, with Tony occasionally being caught referring to her by her first name with even Gibbs joking about how close they were. This was due to Tony's involvement in an ongoing operation of personal importance to Shepard, in which they develop a strong level of trust. Their interactions become more frequent when Tony assumes Gibbs's responsibilities, and they become increasingly familiar as seen in the episode "Shalom". Tony was particularly upset at Shepard's death in "Judgment Day (Part 1)", and blames himself for following Shepard's instruction to abandon her protection detail. In the episode "Agent Afloat", Ziva reveals that, in the aftermath of Shepard's death, Tony has been drinking out of guilt. Male Agents Special Agent Leroy Jethro Gibbs Through flashbacks in the episode "Baltimore", it is shown that Tony first met Gibbs in 2001 when, as a Baltimore PD officer, Tony arrested an undercover Gibbs while they were investigating the same suspect in different cases. When Tony realized that his partner was corrupt, Gibbs took the opportunity to recruit Tony to NCIS and became a mentor to him. Tony greatly respects Gibbs and claims to have a mentor/protégé or father/son relationship with him, a feeling supported by the "tough love" Gibbs often demonstrates. Tony is easily riled when it seems that Gibbs has a new favorite and tries desperately to win back favor. Gibbs has the tendency to smack Tony on the back of the head whenever he says or does something inappropriate, starting with the last flashback sequence of "Baltimore". Tony tolerates being smacked only by Gibbs, reacting angrily when this is done by Todd and Ziva. When Gibbs starts "being nice" in the episode "Kill Ari (Part 1)", Tony irritates Gibbs until he elicits a slap to the back of the head. Tony prides himself on knowing many of the confusing military terms, acronyms, and slang that Gibbs regularly spouts and mimics them. Tony explains this jargon to others (serving as exposition), as well as Gibbs's unorthodox interrogation techniques, often accurately predicting Gibbs's next moves. After Gibbs personally appoints Tony as his replacement at the end of season three, Tony tries to emulate Gibbs's leadership style, though he adds "campfire discussions"