Ariana Kane was The Alliance's head of Counter-Intelligence. She was sent into SD-6 in order to investigate the "murder" of Emily Sloane after it was revealed that an unknown third party had interfered with Arvin Sloane's attempt to poison her, as well as the subsequent blackmailing of Sloane after SD-6's internal attempts to discover the perpetrator were unsuccessful.
As Head of Counter-Intelligence
Upon arrival at SD-6 to investigate the situation surrounding Arvin Sloane at his own request, Ariana Kane immediately launched a witch hunt, specifically focused on Jack Bristow, claiming that everything he did was too perfect adding that "... I mean, he even gets angry when it makes strategic sense." (The Abduction) She believed that he had the perfect motive to blackmail Sloane. Ariana believed several of Jack's missions were suspicious and she heavily investigated them also leading Ariana to question Jack about the death of CIA agent Steven Haladki, as they found his DNA on a gun Jack used from the armory (A Higher Echelon). All of this prompted Jack, with the help of the CIA, to create security footage and hard evidence, proving that he had indeed been in the locations stated by his missions because, during the course of these supposed missions, he was helping out the CIA. This evidence passed Ariana's scrutiny but she was not satisfied. Ariana requested Jack's SIM card to verify phone calls and cell-tower information to more accurately determine whether the information Jack had supplied was accurate. Agent Michael Vaughn attempted to help Jack by posing as a waiter and taking Jack's phone, creating a dummy SIM card and returning the phone but the attempt ultimately failed as the ink had not dried on the dummy SIM card causing a stain on Ariana's hands and Jack went into hiding at the CIA operations base.
Sydney Bristow's cover was nearly blown while having dinner with Vaughn. Ariana's agents identified Vaughn leaving the airport with Sydney and discovered that he worked for the CIA by hacking into the DMV database. Vaughn and Sydney neutralised the agents and Ariana never discovered Sydney's affiliation with the CIA.
Whilst Jack was hiding out with the CIA, he recognized that the easiest way for him to escape suspicion was to find the true perpetrator. He took the information he had obtained to Irina Derevko, who was still a prisoner of the CIA, and they both puzzled over the situation eventually coming to the conclusion that it was actually Ariana herself behind the blackmailing of Sloane after retrieving security tape footage showing Jean Briault, who Arvin Sloane had previously murdered, and Kane in a hotel in Lima, Peru giving her a motive for blackmail: revenge. Although Kane's accounts are shown empty it is later discovered that she deposited the bearer bonds only long enough that she could convert it into cash.
When Jack returns to Irina, she suggests that Sloane requested Kane personally as he knew she would be easy to frame. (The Getaway)
Quotes
"Men always call women crazy when they're caught with their pants down." (The Abduction)
"His answers are too perfect. I mean, he even gets angry when it makes strategic sense." to Arvin Sloane (The Abduction)
"Yes, I read your report. I think either she was an accomplice to his blackmail or else the two of them have been up to something more long-term. You must have noticed that Bristow frequently assigns his daughter to operations of his own design." to Arvin Sloane regarding Sydney and Jack Bristow (The Getaway)
