Nathan Ingram (Brett Cullen) had the most important death on Person of Interest. The series, which lasted for five seasons on CBS, had no shortage of memorable deaths, but the one with the biggest impact out of all of them wasn’t Joss Carter’s - it was Nathan Ingram’s.
Nathan was a key recurring character who made multiple appearances in Harold Finch’s flashbacks. It was revealed early in the series that Nathan Ingram was Finch’s best friend from college and a colleague who worked with him on the Machine. Apparently, it was Nathan and not Finch (Michael Emerson) who received credit for designing it after 9/11. It was decided between the two of them that it would be better if Nathan took the spotlight. Through most of the first two seasons, it was made clear in the show’s present-day scenes that Nathan was no longer alive, but exactly what happened to him wasn’t made clear until the season 2 finale, titled “God Mode”.
Flashbacks in seasons 1 and 2 chronicled the birth of the Machine and the roles that Finch and Nathan played in bringing it online. Nathan was completely supportive at first, but as time passed, he became increasingly uncomfortable with the nature of the Machine and how the government planned to use it. He even tried to take matters into his own hands and save the “irrelevant” people that the government ignored. Later, Nathan tried to expose the Machine by speaking to a reporter. As a result, Nathan was targeted for assassination by the government and killed in the same bombing that gave Finch a permanent limp.
In what was one of the most significant scenes in the show’s five-year history, Finch went to the Machine and simply asked, “did you know?”. Finch then checked the Machine’s files and confirmed what he already feared was true: Nathan’s death was classified as “non-relevant”. In other words, Nathan could have been saved. Then, right before Finch’s eyes, it deleted all the data on the irrelevant numbers – including Nathan’s -- just as it did every day. The Machine was always programmed to act this way, but it was at this moment that the reality of it all really hit home with Finch. It was only then that Finch truly realized the repercussions of what he had created. This revelation made Nathan’s fate all the more tragic.
Finch’s “did you know?” scene in the season 2 finale was extremely powerful, as it perfectly captured the emotional impact that Nathan Ingram’s untimely death had on Finch. Over the course of seasons 1 and 2, Person of Interest slowly evolved Nathan into a deeply human and flawed character who in a lot of ways inspired the ideas that Finch upholds in the present-day story. This scene, combined with Nathan’s own efforts to help the irrelevant numbers, is ultimately what inspired Finch’s mission in Person of Interest.