Doomed Egyptian queen Cleopatra has captured the imaginations of people all over the world for centuries. Archaeologists have long sought to locate her tomb, which she shared with her lover, Mark Antony, per popular legend. Thus far, the search has been unsuccessful, although many believe she would have been buried near the royal palace in Alexandria, Egypt.

National Geographic explorer Kathleen Martinez thinks she might be on the verge of locating Cleopatra’s final resting place at a site called Taposiris Magna. Her 20-year journey (and counting) to prove her hypothesis—and the exciting new discovery of a submerged ancient port several miles off the Mediterranean shore that was likely once part of that temple—are chronicled in Cleopatra’s Final Secret, a new documentary film from National Geographic.

Martinez has a degree in archaeology but initially became a criminal lawyer. She brought that legal training to bear on the question of the location of Cleopatra’s tomb, treating it as she would a forensic case. “I tried to understand her personality, who were her friends, who were her enemies,” Martinez told Ars. “She was a strategist and she always had a Plan A and a Plan B.” It simply made sense to her that Cleopatra would have brought that same strategic thinking to orchestrating her death. Martinez suggested that the queen arranged for loyal subjects to transport her body through secret tunnels to a hidden final resting place.

Martinez knows firsthand how difficult it can be for inmates to receive food and other items from family and friends, all of which are searched before reaching the intended recipient. Cleopatra was imprisoned in her palace, and legend has it that an ally brought her a basket of figs, and hidden within was the cobra that gave the Egyptian queen that fatal bite. Martinez pondered why Cleopatra would have bothered with an actual cobra when all she needed was the venom, mixed in with food or drink.

Martinez believes it was because the cobra is associated with Isis in Egyptian mythology, and Cleopatra had fashioned her image as being a human representation of the goddess. “It was the symbolism,” said Martinez. “She was dying, but she was dying as Isis, as a goddess, not as a prisoner. And this is how she became a legend, a myth.” It stood to reason, then, that given the choice, Cleopatra could have arranged for her body (and that of Antony) to be buried in a temple of Isis—a conclusion supported by Petrarch’s writings, among other sources.