Petra Shirazi is an agent with the Agency.
That term is often used for denote the CIA but in this case it might not be since there are numerous references to the CIA doing something, each time it is phrased as though it was a different organization than the one Shirazi works for. To further that though, operatives within the organization talk once or twice about things like needing "access to databases as the FBI, CIA, and Homeland".
The action in the series takes place a handful of years in the future [first adventure published in 2014 concerning the year 2021] with occasional flashbacks a few years before. Further, though the main character is, in my opinion, Shirazi, her actions are all in action against and then in conjunction with a highly dangerous Iranian assassin known as the Ahriman. In fact the three-book series is entitled The Ahriman Legacy as it deals with the ramifications of a recruitment by Shirazi gone wrong and the resultant creation of a near-legendary assassin.
The trilogy is definitely a love story but one filled with considerable action and intrigue. Before the first recorded adventure, we learn through flashback how Shirazi is assigned by the Agency to head to Tehran to work as a field agent. There she will meet and become intimately close to Kasem Ismaili. When the counter-intelligence people begin to suspect her, she is forced to flee but Kasem is ensnared by a rogue Iranian general and "duped into working as an assassin", all to pay for the ransom of the woman he loved but who had not actually been captured. Such was how and why Kasem became the Ahriman.
Shirazi will change employment during the course of this series and will find herself first pulled back unwillingly to work for the Agency yet again and then will have to team up with her former lover turned adversary turned lover, Kasem Ismaili, aka the Ahriman.