Kruger was born with an IQ of 197. He was recruited by the CIA after his graduation from the Massachusetts Institute of Technology, at the age of eighteen. He worked for six years as a weapons design developer but he had problems dealing with authority, resulting in his transfer to field operations in China. After eight years, he was transferred to the CIA headquarters, where he eventually obtained the position of Assistant Director of Operations. During this time, he also visited Saudi Arabia's capital, Riyadh, for an unspecified field operation while in the company of his aide, Olivia Hopkins. Although he is married, he has an affair with Hopkins and was with her when fellow CIA agent John Summers was murdered.
Secrets and LiesEdit
Immediately after entering the CIA headquarters, the BAU is introduced to Kruger by Deputy Director of Operations Bruno Hawks, along with Hopkins and the Associate Director of Operations, Gina Sanchez. The four become the BAU's main suspects of being the mole working for Saudi terrorist Hassan Nadir because Summers had four suspects himself, and they all have field experience in Saudi Arabia unlike the rest of Bruno's unit. The BAU assigns Reid to observe Kruger while he directs the search efforts for Nadir's wife, Aaliyah, who was taken into the U.S. with her two children by Summers before his death. Reid suggests publicizing Aaliyah's image, but Kruger rejects it, arguing that it is nonsensical because Aaliyah is officially dead. Kruger then instructs some men under his command to form small groups and look for Aaliyah in Arab-populated areas where she would feel more comfortable, but he is interrupted by Reid, who suggests that they should profile Summers first.
Although Kruger shows a general disdain for Reid's input, he eventually agrees to look for Aaliyah in empty industrial areas and storage facilities in the area surrounding Summers's residence, owing to Summers's solitary and paranoid nature. Kruger sarcastically thanks Reid for helping him reach this conclusion. After noticing Hopkins being subjected to a harsh interrogation by Elle, Kruger intervenes, arguing that Hopkins's civil rights are being violated. However, Bruno informs him that their rights are revoked until the mole is identified and Aaliyah is found. As Elle presses Hopkins to reveal her whereabouts in the night of Summers's murder, Kruger intervenes again and says that they were together in her home. Gideon reminds him that he is married and asks when he returned to his wife. After a moment of hesitation, Kruger says that his wife will confirm that he came home at 1:30 a.m., and that they are only guilty of having an affair. In response, Bruno tells him that he will subject them to a disciplinary measure. Kruger follows Hopkins and tries to talk to her, but she stops him.
Minutes later, Hopkins is murdered by Bruno while she is attempting to look up information on his own activities in Saudi Arabia. In order to incriminate Kruger, Bruno infects Hopkins's computers and blockades the room's CCTV with a virus he placed in Kruger's computer three weeks before. After discovering Hopkins's body, the BAU summons Hawks, Sanchez, and Kruger to tell them about the murder and observe their reactions. Kruger is the most shocked of the three by far: he first accuses the BAU of lying, manifests his incredulity about anyone being murdered in CIA headquarters, demands to know Hopkins's real whereabouts, and finally lambastes Sanchez for looking at him like he was already proven guilty of being the mole. After this, both Sanchez and Kruger exit the room, but he is later stopped by the BAU. Kruger denies being the mole once again and says that the virus being placed in his computer is a trap.
When the BAU figures out the location of Aaliyah by reexamining Summers's recordings, Gideon publicly clears Sanchez and orders Kruger to be disarmed and taken into custody. He informs Bruno that Kruger's actions are in line with those of a man who killed a loved one, and that betraying his country was part of the course after having betrayed both his wife and Hopkins. However, this is actually a stunt to trick Bruno into exposing himself, since they believe that he is the real mole. They tell Kruger so with a handwritten note, and Kruger unwittingly confirms that they are right and that he is innocent: Kruger believes that the note is a trick to incriminate himself and he refuses to cooperate, instead of seizing the opportunity to incriminate Bruno.